github-label-sync: add page (#2967)

pages/common/github-label-sync.md

@@ -0,0 +1,24 @@
+# github-label-sync
+
+> A command line interface for synchronising GitHub labels.
+> Homepage: <https://npmjs.com/package/github-label-sync>.
+
+- Synchronise labels using a local `labels.json` file:
+
+`github-label-sync --access-token {{token}} {{repository_name}}`
+
+- Synchronise labels using a specific labels JSON file:
+
+`github-label-sync --access-token {{token}} --labels {{url|path/to/json_file}} {{repository_name}}`
+
+- Perform a dry run instead of actually synchronising labels:
+
+`github-label-sync --access-token {{token}} --dry-run {{repository_name}}`
+
+- Keep labels that aren't in `labels.json`:
+
+`github-label-sync --access-token {{token}} --allow-added-labels {{repository_name}}`
+
+- Synchronise using the `GITHUB_ACCESS_TOKEN` environment variable:
+
+`github-label-sync {{repository_name}}`