Added github action (Ubuntu).

.github/workflows/cmake.yml

@@ -0,0 +1,55 @@
+name: CMake
+
+on: [push]
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: RelWithDebInfo
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-20.04]
+        include:
+        - os: macos-latest
+        - os: ubuntu-latest
+        - os: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Install Dependencies
+      run: sudo apt-get install libpcre3-dev libgtkmm-3.0-dev
+
+    - name: Create Build Environment
+      run: cmake -E make_directory ${{runner.workspace}}/build
+
+    - name: Configure CMake
+      # Use a bash shell so we can use the same syntax for environment variable
+      # access regardless of the host operating system
+      shell: bash
+      working-directory: ${{runner.workspace}}/build
+      # Note the current convention is to use the -S and -B options here to specify source 
+      # and build directories, but this is only available with CMake 3.13 and higher.  
+      # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
+      run: cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+
+    - name: Build
+      working-directory: ${{runner.workspace}}/build
+      shell: bash
+      # Execute the build.  You can specify a specific target with "--target <NAME>"
+      run: cmake --build . --config $BUILD_TYPE
+
+#    - name: Pack
+#      working-directory: ${{runner.workspace}}/build
+#      shell: bash
+#      run: cmake --build . --config $BUILD_TYPE --target package
+
+#    - name: Test
+#      working-directory: ${{runner.workspace}}/build
+#      shell: bash
+#      # Execute tests defined by the CMake configuration.
+#      # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
+#      run: ctest -C $BUILD_TYPE