Switch to actions/labeler@v4 for labeling PRs. (#14203)

This has a number of advantages:

- It allows us to make PR labeling event-driven instead of polling.
  This, in turn, means that it only runs when a PR is modified, and only
  evaluates that specific PR, which results in spending far less time
  running PR labeler jobs.
- This is the ‘official’ way to handle PR labels automatically as code,
  and thus Ilya will no longer need to maintain a custom labeling action
  for this purpose.
- The matching syntax supported by this action is more expressive than
  what is supported by our existing infrastructure, allowing for things
  sucha s requring all of a group of files to be modified in a PR for it
  to have a specific label applied. We have no need right now for this,
  but it is useful to have it available long-term.
- Because the labeling is PR-triggered, it shows up in the PR checks, so
  we can more easily see if auto-labeling has run for a given PR or not.

1 files changed, 12 insertions, 9 deletions

diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
index 0854080a70..2b8b41fcb0 100644
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@@ -2,17 +2,20 @@
 # Handles labelling of PR's.
 name: Pull Request Labeler
 on:
-  schedule:
-    - cron: '*/10 * * * *'
-env:
-  DISABLE_TELEMETRY: 1
+  pull_request_target: null
+concurrency:
+  group: pr-label-${{ github.ref }}
+  cancel-in-progress: true
 jobs:
   labeler:
+    name: Apply PR Labels
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
     steps:
-      - uses: docker://docker.io/ilyam8/periodic-pr-labeler:v0.1.0
+      - uses: actions/labeler@v4
         if: github.repository == 'netdata/netdata'
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          GITHUB_REPOSITORY: ${{ github.repository }}
-          LABEL_MAPPINGS_FILE: .github/labeler.yml
+        with:
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+          sync-labels: true