chore: limit concurrency for build jobs (#4929)

* Configure build jobs to cancel previous builds when new changes
  are pushed to a pull request branch, and serialize builds when
  running in a branch from a push event
* Reduce privileges of GitHub token for scripts workflow

.github/workflows/installer.yml

@@ -12,6 +12,13 @@ on:
     paths:
       - "install.sh"
 
+# Cancel in-progress runs for pull requests when developers push
+# additional changes, and serialize builds in branches.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-using-concurrency-to-cancel-any-in-progress-job-or-run
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   ubuntu:
     name: Test installer on Ubuntu