Squashed commit of star-bnl#436

Author: plexoos

.clang-format

@@ -0,0 +1,11 @@
+---
+BasedOnStyle: Google
+ColumnLimit: '120'
+IndentPPDirectives: None
+IndentWidth: '3'
+MaxEmptyLinesToKeep: '1'
+SpacesInParentheses: 'false'
+TabWidth: '3'
+UseTab: Never
+
+...

.github/workflows/check-format.yml

@@ -0,0 +1,19 @@
+name: clang-format Check
+on: [push, pull_request]
+jobs:
+  formatting-check:
+    name: Formatting Check
+    runs-on: ubuntu-latest
+    steps:
+    #this is needed to get sha of central repo
+    - name: test_Files
+      uses: actions/checkout@v3
+      with:
+          fetch-depth: 0  # OR "2" -> To retrieve the preceding commit.
+    - name: Run clang-format style check for C/C++ files.
+      uses: DanielWielanek/clang-format-action@main
+      with:
+        clang-format-version: '13'
+        check-path: '.'
+        upstream-branch: upstream/main
+        upstream-path: https://github.com/star-bnl/star-sw.git