Move external-contributer label workflow into labeler.yml as 'pull_request_target' cannot be used

Author: andersfugmann

.github/workflows/label-external-contributions.yml

@@ -142,3 +142,65 @@ jobs:
         with:
           repo-token: "${{ github.token }}"
           pr-number: ${{ steps.validate.outputs.pr_numbers }}
+
+      - name: Label external contributions
+        if: steps.validate.outputs.has_prs == 'true'
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR_NUMBERS: ${{ steps.validate.outputs.pr_numbers }}
+        run: |
+          set -euo pipefail
+
+          label="external-contribution"
+          cutoff=$(date -u -d "24 hours ago" "+%Y-%m-%dT%H:%M:%SZ")
+          while IFS= read -r pr_number; do
+            if [[ ! "$pr_number" =~ ^[1-9][0-9]*$ ]]; then
+              echo "Skipping malformed pull request number."
+              continue
+            fi
+
+            pr_json=$(gh api "repos/$REPO/pulls/$pr_number")
+            if ! jq -e \
+              --arg repo "$REPO" \
+              --arg label "$label" \
+              '.state == "open" and
+               .draft == false and
+               .base.repo.full_name == $repo and
+               .head.repo.full_name != $repo and
+               .user.type == "User" and
+               .author_association != "MEMBER" and
+               .author_association != "OWNER" and
+               (any(.labels[]?; .name == $label) | not)' \
+              >/dev/null <<<"$pr_json"; then
+              continue
+            fi
+
+            events=$(gh api --paginate \
+              "repos/$REPO/issues/$pr_number/events?per_page=100" |
+              jq -cs 'add')
+
+            if ! jq -e -s --arg cutoff "$cutoff" \
+              '.[0].created_at >= $cutoff or
+               any(.[1][];
+                 (.event == "reopened" or .event == "ready_for_review") and
+                 .created_at >= $cutoff)' \
+              <(printf '%s\n' "$pr_json") \
+              <(printf '%s\n' "$events") \
+              >/dev/null; then
+              continue
+            fi
+
+            if jq -e --arg label "$label" \
+              'any(.[]; .event == "unlabeled" and .label.name == $label)' \
+              >/dev/null <<<"$events"; then
+              continue
+            fi
+
+            jq -n --arg label "$label" '{labels: [$label]}' |
+              gh api --method POST \
+                "repos/$REPO/issues/$pr_number/labels" \
+                --input - \
+                >/dev/null
+            echo "Labelled pull request #$pr_number."
+          done <<<"$PR_NUMBERS"