ci: improve the GitHub Actions workflow (#2697)

* set a timeout of 30 minutes - our CI rarely takes more than that. Let's not use quotas unecessarily
* use concurrency to cancel previous workflows

Author: thatfiredev

.github/workflows/android.yml

@@ -1,12 +1,17 @@
 name: Android CI
 
 on:
-  - pull_request
-  - push
+  pull_request:
+  push:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   build:
     runs-on: ubuntu-latest
+    timeout-minutes: 30
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK 17