fluxcd/update-script: add double quotes to prevent globbing and word splitting

OLD_VERSION="$(nix-instantiate --eval -E "with import $NIXPKGS_PATH {}; fluxcd.version or (builtins.parseDrvName fluxcd.name).version" | tr -d '"')"

LATEST_TAG=$(curl ${GITHUB_TOKEN:+" -u \":$GITHUB_TOKEN\""} --silent https://api.github.com/repos/fluxcd/flux2/releases/latest | jq -r '.tag_name')

LATEST_VERSION=$(echo ${LATEST_TAG} | sed 's/^v//')

LATEST_VERSION=$(echo "${LATEST_TAG}" | sed 's/^v//')

if [ ! "$OLD_VERSION" = "$LATEST_VERSION" ]; then

    SHA256=$(nix-prefetch-url --quiet --unpack https://github.com/fluxcd/flux2/archive/refs/tags/${LATEST_TAG}.tar.gz)

    SHA256=$(nix hash convert --hash-algo sha256 --to sri $SHA256)

    SPEC_SHA256=$(nix-prefetch-url --quiet --unpack https://github.com/fluxcd/flux2/releases/download/${LATEST_TAG}/manifests.tar.gz)

    SPEC_SHA256=$(nix hash convert --hash-algo sha256 --to sri $SPEC_SHA256)

    SHA256=$(nix-prefetch-url --quiet --unpack "https://github.com/fluxcd/flux2/archive/refs/tags/${LATEST_TAG}.tar.gz")

    SHA256=$(nix hash convert --hash-algo sha256 --to sri "$SHA256")

    SPEC_SHA256=$(nix-prefetch-url --quiet --unpack "https://github.com/fluxcd/flux2/releases/download/${LATEST_TAG}/manifests.tar.gz")

    SPEC_SHA256=$(nix hash convert --hash-algo sha256 --to sri "$SPEC_SHA256")

    setKV () {

        sed -i "s|$1 = \".*\"|$1 = \"${2:-}\"|" "${FLUXCD_PATH}/package.nix"

    }

    setKV version ${LATEST_VERSION}

    setKV sha256 ${SHA256}

    setKV manifestsSha256 ${SPEC_SHA256}

    setKV version "${LATEST_VERSION}"

    setKV sha256 "${SHA256}"

    setKV manifestsSha256 "${SPEC_SHA256}"

    setKV vendorHash "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=" # The same as lib.fakeHash

    set +e

    VENDOR_HASH=$(nix-build --no-out-link -A fluxcd $NIXPKGS_PATH 2>&1 >/dev/null | grep "got:" | cut -d':' -f2 | sed 's| ||g')

    VENDOR_HASH=$(nix hash convert --hash-algo sha256 --to sri $VENDOR_HASH)

    VENDOR_HASH=$(nix-build --no-out-link -A fluxcd "$NIXPKGS_PATH" 2>&1 >/dev/null | grep "got:" | cut -d':' -f2 | sed 's| ||g')

    VENDOR_HASH=$(nix hash convert --hash-algo sha256 --to sri "$VENDOR_HASH")

    set -e

    if [ -n "${VENDOR_HASH:-}" ]; then

        setKV vendorHash ${VENDOR_HASH}

        setKV vendorHash "${VENDOR_HASH}"

    else

        echo "Update failed. VENDOR_HASH is empty."

        exit 1