.github/workflows: delete pr.yml

Allow pull requests. Going to try not using Gerrit.

.github/workflows/pr.yml

@@ -1,34 +0,0 @@
-name: PR
-on:
-  pull_request_target:
-    branches: [main]
-    types: [opened]
-permissions:
-  contents: read
-jobs:
-  close:
-    permissions:
-      contents: read
-      # We have to use two different APIs below,
-      # so just grant two different permissions.
-      issues: write
-      pull-requests: write
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4.2.2
-      - uses: actions/github-script@v7.0.1
-        with:
-          script: |
-            const fs = require('fs');
-            console.log(await github.rest.issues.createComment({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              issue_number: context.issue.number,
-              body: fs.readFileSync('CONTRIBUTING.md', { encoding: 'utf8', }),
-            }));
-            console.log(await github.rest.pulls.update({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number: context.issue.number,
-              state: 'closed',
-            }));

CONTRIBUTING.md

@@ -1,2 +1 @@
-RE2 uses Gerrit instead of GitHub pull requests.
 See the [Contribute](https://github.com/google/re2/wiki/Contribute) wiki page.