CI: added build & test CI

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: C CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Configure Cmake
+      run: |
+        mkdir build
+        cd build
+        cmake ..
+    - name: Build
+      run: cmake --build .
+    - name: Test
+      run: ctest --verbose