Add clang-format 20 (#237)

Co-authored-by: Johanan <git@johanan.dev>

Author: offa

.github/workflows/tests.yml

@@ -39,6 +39,7 @@ jobs:
           - 17
           - 18
           - 19
+          - 20
     steps:
     - uses: actions/checkout@v4
     - name: Build and test the Docker image
@@ -67,6 +68,7 @@ jobs:
           - 17
           - 18
           - 19
+          - 20
         path:
           - check: 'test/known_fail'
             exclude: 'capital'

README.md

@@ -26,6 +26,7 @@ You can define your own formatting rules in a `.clang-format` file at your repos
 * 17: `clang-format-17`
 * 18: `clang-format-18`
 * 19: `clang-format-19`
+* 20: `clang-format-20`
 
 ## Action version upgrade guarantee