workflow: explicit permissions on pr.yml (#22)

* workflow: explicitly assign permissions for pr.yml

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

* Add pull-requests permission to PR workflow

---------

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: jimschubert

.github/workflows/pr.yml

@@ -19,6 +19,10 @@ name: Build Go (PR)
 on:
   pull_request:
 
+permissions:
+  contents: read
+  pull-requests: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true