Lock clang-format version (#158)

* install clang-format using pip

* update readme to include note on installation of format dependencies

.github/workflows/style.yml

@@ -15,7 +15,7 @@ env:
 
 jobs:
   build:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v2
@@ -26,9 +26,7 @@ jobs:
           key: ${{ github.workflow }}-cpm-modules-${{ hashFiles('**/CMakeLists.txt', '**/*.cmake') }}
 
       - name: Install format dependencies
-        run: |
-          brew install clang-format
-          pip3 install cmake_format==0.6.11 pyyaml
+        run: pip3 install clang-format==14.0.6 cmake_format==0.6.11 pyyaml
 
       - name: configure
         run: cmake -Stest -Bbuild