port label sync from pymc-marketing

.github/workflows/pr-auto-label.yml

@@ -0,0 +1,40 @@
+name: "Pull Request Labeler"
+on:
+- pull_request_target
+
+jobs:
+  sync:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+    - name: Sync labels with closing issues
+      run: |
+        owner="pymc-devs"
+        name="pymc"
+        pr_number=${{ github.event.pull_request.number }}
+
+        labels=$(gh api graphql --paginate -F number=$pr_number -F owner=$owner -F name=$name -f query='
+          query($endCursor: String, $owner: String!, $name: String!, $number: Int!) {
+            repository(owner: $owner, name: $name) {
+              pullRequest(number: $number) {
+                closingIssuesReferences(first: 10, after: $endCursor) {
+                  nodes {
+                    labels(first: 10) {
+                      nodes {
+                        name
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+          ' --jq '.data.repository.pullRequest.closingIssuesReferences.nodes | map(.labels.nodes | map(.name)) | flatten | unique | join(",")')
+
+        gh pr edit $pr_number --add-label "$labels"
+      env:
+        GH_TOKEN: ${{ github.token }}