Temporarily workaround alpine issue

Corrected README Setting a schedule configuration example

Until a new alpine image is created, we should ensure the latest
packages are used, and therefore we should upgrade default
installed packages.

Without this patch, we'll have outdated and vulnerable packages
until a new 3.12 image is released.

This is a problem, as we'll publish broken images.

This should temporarily workaround it, at the expense of larger
images (contains package cache)

Fix comment spacing

Without this patch, chart linting will fail: more than two
spaces are needed before a comment in the helm chart values.

This fixes it by adding one more space, and move the whole block
of comments for consistency.

Publish image on tag with github actions

As we are pretty much committed to github actions, we should
probably rely on it to push the images at each commit merged
on the master branch.

This is to be on par with the previous documentation.

As we are pretty much committed to github actions, we should
probably rely on it to push the images on tag.

This covers the missing bits.

Fix typo in github workflows

Without this patch, the PR jobs are broken and no jobs are running.
This was a recently introduced typo in the last refactor of the
PR jobs.

This should fix it, and make the PR test working again.

Merge pull request #220 from weaveworks/dependabot/go_modules/github.com/prometheus/client_golang-1.8.0

Bump github.com/prometheus/client_golang from 1.0.0 to 1.8.0

Force golang version

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.0.0 to 1.8.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/master/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.0.0...v1.8.0

)

Signed-off-by: dependabot[bot] <support@github.com>

Bump github.com/prometheus/common from 0.4.1 to 0.15.0

Bumps [github.com/prometheus/common](https://github.com/prometheus/common) from 0.4.1 to 0.15.0.
- [Release notes](https://github.com/prometheus/common/releases)
- [Commits](https://github.com/prometheus/common/compare/v0.4.1...v0.15.0

)

Signed-off-by: dependabot[bot] <support@github.com>

Bump github.com/spf13/cobra from 1.0.0 to 1.1.1

Bumps [github.com/spf13/cobra](https://github.com/spf13/cobra) from 1.0.0 to 1.1.1.
- [Release notes](https://github.com/spf13/cobra/releases)
- [Changelog](https://github.com/spf13/cobra/blob/master/CHANGELOG.md)
- [Commits](https://github.com/spf13/cobra/compare/v1.0.0...v1.1.1

)

Signed-off-by: dependabot[bot] <support@github.com>

Bump github.com/sirupsen/logrus from 1.2.0 to 1.7.0

Without this, golang version used is the golang version decided
by github.

This is a problem, as it might shift over time, without our control.

This fixes it by getting the golang version from the go.mod.

Bumps [github.com/sirupsen/logrus](https://github.com/sirupsen/logrus) from 1.2.0 to 1.7.0.
- [Release notes](https://github.com/sirupsen/logrus/releases)
- [Changelog](https://github.com/sirupsen/logrus/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sirupsen/logrus/compare/v1.2.0...v1.7.0

)

Signed-off-by: dependabot[bot] <support@github.com>

Do not bump kubernetes with dependabot

Merge k8s and go updates

Without this patch, we'll get kubernetes updates.

This is not necessary, and could be even a problem on merge:
those kubernetes updates are done separately, knowingly,
to respect the life cycle of the kubernetes we need
(and stay one version below latest to have a larger coverage
of versions).

We could keep dependabot to update those on a lower frequency,
but that sounds clunky and not great. Instead disable them all,
and rely on the team to do this regular maintenance work.

Fix chart linter

Merge remote-tracking branch 'upstream/dependabot/go_modules/k8s.io/apimachinery-0.19.2' into merge-k8s-and-go-updates

Merge remote-tracking branch 'upstream/dependabot/go_modules/k8s.io/kubectl-0.19.4' into merge-k8s-and-go-updates

There are lots of duplicated code in this workflow.
This fixes it by making a unique job with parameters. The
matrix buys us the parallelisation and the fail-fast.

Without this patch, the lint action incorrectly returns everything
is fine.

This is a problem, as lint effectively is not running, and
therefore we could merge broken charts.

This fixes it by updating to the latest practices you can find
in the official chart-repo-actions.

(See the official example in
ihttps://github.com/helm/charts-repo-actions-demo/blob/1a9640d9983d983404862daee9563fd871db3874/.github/workflows/lint-test.yaml)

Bump nick-invision/retry from v1 to v2.2.0

Bumps [nick-invision/retry](https://github.com/nick-invision/retry) from v1 to v2.2.0.
- [Release notes](https://github.com/nick-invision/retry/releases)
- [Changelog](https://github.com/nick-invision/retry/blob/master/.releaserc.js)
- [Commits](https://github.com/nick-invision/retry/compare/v1...fb3bca3fb54f6488d7508c8d1eeb64b94efd5a93

)

Signed-off-by: dependabot[bot] <support@github.com>

Cleanup github actions

Without this, it's a little bit hard to grasp how things
are interconnected. This should clarify things.

- Made all the file extensions ".yaml"
- Regrouped actions together to make it easy to see when they
  are useful: on-pr is useful at every PR, on-tag when we are
  ready to tag next image, on-pr-chart when we have a PR to
  modify the chart with the published image, on-release when
  we have released and need to publish the final helm chart
- Regrouped periodic jobs together, to deal with stale prs/issues
  and ensuring that our helm chart always works.

Add more logs into gates

This will be necessary to find out why some docker containers fail
to come back up in github actions.