Add Github action to ensure PR's have an associated issue

Author: eleanorjboyd

.github/workflows/pr-file-check.yml

@@ -42,3 +42,15 @@ jobs:
             .github/test_plan.md
           skip-label: 'skip tests'
           failure-message: 'TypeScript code was edited without also editing a ${file-pattern} file; see the Testing page in our wiki on testing guidelines (the ${skip-label} label can be used to pass this check)'
+
+      - name: 'Ensure PR has an associated issue'
+        uses: actions/github-script@v6
+        with:
+          script: |
+            const labels = context.payload.pull_request.labels.map(label => label.name);
+            if (!labels.includes('skip-issue-check')) {
+              const issueNumber = context.payload.pull_request.body.match(/#(\d+)/);
+              if (!issueNumber) {
+                core.setFailed('No associated issue found in the PR description.');
+              }
+            }