Increase PR build workflow timeout (#6931)

PRs that result in changes occurring in every service package (e.g.
version bump) increases the import time. Inrease the timeout to
compensate.

Author: dagnir

.github/workflows/pull-request-build.yml

@@ -53,4 +53,4 @@ jobs:
             --branch "$HEAD_REF" \
             --pr-number "$PR_NUMBER" \
             --run-id "${{ github.run_id }}"
-        timeout-minutes: 120
+        timeout-minutes: 180