ci: rename build.yml to ci.yml for cross-repo consistency

Author: cewert

.github/workflows/build.yml .github/workflows/ci.yml.github/workflows/build.yml renamed to .github/workflows/ci.yml

@@ -1,11 +1,19 @@
-name: Test if build is working
+name: CI
 
 on:
   pull_request:
-      types: [opened, synchronize]
+    branches: [main]
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
 
 jobs:
-  test:
+  build:
     runs-on: ubuntu-latest
     steps:
       - name: Generate GitHub App Token