Declaratively define (and sync) labels

This adds a GitHub Action workflow to sync the labels from a YAML file
in `.github/labels.yaml`, in combination with fetching the standard
labels from `fluxcd/community`.

At present, there are no custom labels for the repository itself. But
the `.github/labels.yaml` file is added as boilerplate.

Signed-off-by: Hidde Beydals <[email protected]>

Author: hiddeco

.github/dependabot.yaml

@@ -3,7 +3,7 @@ version: 2
 updates:
   - package-ecosystem: "github-actions"
     directory: "/"
-    labels: ["area/build"]
+    labels: ["area/ci", "dependencies"]
     schedule:
-      # by default this will be on a monday.
+      # By default, this will be on a monday.
       interval: "weekly"

.github/labels.yaml

@@ -0,0 +1,7 @@
+# Configuration file to declaratively configure labels
+# Ref: https://github.com/EndBug/label-sync#Config-files
+
+# TODO: enable this when we have a release/v1.0.x branch
+#- name: backport:release/v1.0.x
+#  description: To be backported to release/v1.0.x
+#  color: '#ffd700'

.github/workflows/sync-labels.yaml

@@ -0,0 +1,28 @@
+name: sync-labels
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+    paths:
+      - .github/labels.yaml
+
+permissions:
+  contents: read
+
+jobs:
+  labels:
+    name: Run sync
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+    steps:
+      - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+      - uses: EndBug/label-sync@da00f2c11fdb78e4fae44adac2fdd713778ea3e8 # v2.3.2
+        with:
+          # Configuration file
+          config-file: |
+            https://raw.githubusercontent.com/fluxcd/community/main/.github/standard-labels.yaml
+            .github/labels.yaml
+          # Strictly declarative
+          delete-other-labels: true