GitHub: import a workflow running the tests

.github/workflows/deforaos-c-ci_ubuntu-latest.yml

@@ -0,0 +1,17 @@
+name: DeforaOS C CI (ubuntu-latest)
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: tests
+      run: make tests