[Infra] Bump clang-format to v15

Author: ncooke3

.github/workflows/check.yml

@@ -36,7 +36,7 @@ jobs:
     - name: Setup check
       run: |
         brew update
-        brew install clang-format@14
+        brew install clang-format@15
         brew install mint
         mint bootstrap
 

README.md

@@ -209,7 +209,7 @@ GitHub Actions will verify that any code changes are done in a style compliant
 way. Install `clang-format` and `mint`:
 
 ```console
-brew install clang-format@14
+brew install clang-format@15
 brew install mint
 ```