Add Labeler

In this commit, we are adding a labelling workflow using Labeler, which will add a helpful label to sample-app-related PRs

.github/labeler.yml

@@ -0,0 +1,8 @@
+# This is used with the label workflow which will triage pull requests and apply a label based on the paths that are
+# modified in the pull request. For more information, see: https://github.com/actions/labeler
+
+'InstrumentationSampleApp':
+- all:
+  - changed-files:
+    - any-glob-to-any-file: ['sample-apps/**/*']
+    - all-globs-to-any-file: ['!sample-apps/prometheus-sample-app/**/*']

.github/workflows/labeler.yml

@@ -0,0 +1,12 @@
+name: "Pull Request Labeler"
+on:
+  - pull_request_target
+
+jobs:
+  labeler:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v5