Added a Github Action for CMake (#6542)

.github/workflows/build_servers_cmake.yml

@@ -0,0 +1,46 @@
+name: Build servers with CMake
+# build_servers_cmake.yml
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    paths:
+      # Always trigger all Github Actions if an action or something CI related was changed
+      - '.github/workflows/**'
+      - 'tools/ci/**'
+      # This workflow should run when a file in a source directory has been modified.
+      - 'src/**'
+      - '3rdparty/**'
+
+jobs:
+  build:
+    # Github Actions checks for '[ci skip]', '[skip ci]', '[no ci]', '[skip actions]', or '[actions skip]' but not a hyphenated version.
+    # It's a catch-all incase a Pull Request has been opened and someone is on auto-pilot.
+    if: "!contains(github.event.head_commit.message, 'ci-skip')"
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+          # The ubuntu-latest label currently points to ubuntu-18.04.
+          # Available: ubuntu-20.04, ubuntu-18.04
+          os: [ubuntu-latest]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      # Install latest CMake.
+      - uses: lukka/get-cmake@latest
+
+      - name: Create build directory
+        run: mkdir cbuild
+
+      - name: Create Unix Makefiles
+        run: |
+          cd cbuild
+          cmake -G "Unix Makefiles" ..
+
+      - name: Command - make
+        run: |
+          cd cbuild
+          make