add ci for c++ gtest

.github/workflows/c++-test.yml

@@ -0,0 +1,26 @@
+name: C++ CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Install dependencies
+      run: sudo apt-get update && sudo apt-get install -y build-essential cmake
+
+    - name: Build
+      run: cd ./c++/gtest_mini_project
+      run: cmake .. && make
+
+    - name: Test
+      run: cd ./c++/gtest_mini_project
+