chore: add not-accepted github workflow

.github/workflows/close-tagged-pr.yml

@@ -0,0 +1,37 @@
+name: Auto-Close PRs with Specific Tag
+
+on:
+  pull_request:
+    types: [opened, labeled]
+
+jobs:
+  close_pr:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check PR Labels
+        id: check-label
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const prNumber = context.payload.pull_request.number;
+            const labels = context.payload.pull_request.labels.map(label => label.name);
+            const forbiddenLabel = "not-accepted";
+
+            if (labels.includes(forbiddenLabel)) {
+              await github.rest.pulls.update({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                pull_number: prNumber,
+                state: "closed"
+              });
+
+             await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: prNumber,
+                body: `**Thank you for your pull request and changes.**
+            Due to a change in our contribution guideline policy, we are closing this pull request as it does not meet the contribution criteria.
+            Please [see here for more details](https://github.com/Consensys/gnark/blob/master/CONTRIBUTING.md#guidelines-for-non-code-and-other-trivial-contributions).`
+              });
+            }