Grant issue write permissions to the issue reviver workflow.

The `issue_reviver` job requires write access to issues to be able to reopen
them.

PiperOrigin-RevId: 800131706

Author: ayushr2

.github/workflows/issue_reviver.yml

@@ -8,6 +8,8 @@ name: "Issue reviver"
 jobs:
   issue_reviver:
     runs-on: ubuntu-latest
+    permissions:
+      issues: write
     steps:
     - uses: actions/checkout@v5
       if: github.repository == 'google/gvisor'