build(deps): bump github.com/containrrr/shoutrrr from 0.5.1 to 0.5.2

Bumps [github.com/containrrr/shoutrrr](https://github.com/containrrr/shoutrrr) from 0.5.1 to 0.5.2.
- [Release notes](https://github.com/containrrr/shoutrrr/releases)
- [Changelog](https://github.com/containrrr/shoutrrr/blob/main/goreleaser.yml)
- [Commits](https://github.com/containrrr/shoutrrr/compare/v0.5.1...v0.5.2

)

---
updated-dependencies:
- dependency-name: github.com/containrrr/shoutrrr
  dependency-type: direct:production
  update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -3,7 +3,7 @@ module github.com/weaveworks/kured
 go 1.16
 
 require (
-	github.com/containrrr/shoutrrr v0.5.1
+	github.com/containrrr/shoutrrr v0.5.2
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/prometheus/client_golang v1.11.0
 	github.com/prometheus/common v0.31.1

go.sum

@@ -99,8 +99,8 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
-github.com/containrrr/shoutrrr v0.5.1 h1:who87ACg0spQdbImaFMsOSh3g2FWyeN5nmO8tCg3llQ=
-github.com/containrrr/shoutrrr v0.5.1/go.mod h1:XSU8tOIZ1JG8m6OuPozfGLpj6Ed+S8ZrRJaEodQhbzw=
+github.com/containrrr/shoutrrr v0.5.2 h1:97P+wZDpN2gzBKLt4PDP1ZUTLz+k8AJVs40WOu9NNw8=
+github.com/containrrr/shoutrrr v0.5.2/go.mod h1:XSU8tOIZ1JG8m6OuPozfGLpj6Ed+S8ZrRJaEodQhbzw=
 github.com/coreos/bbolt v1.3.2/go.mod h1:iRUV2dpdMOn7Bo10OQBFzIJO9kkE559Wcmn+qkEiiKk=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
 github.com/coreos/etcd v3.3.13+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=