CI: Enable the preinstalled MSYS2 in autoformat runs

Shouldn't make much of a difference in this case as build workflows are the bottleneck currently, but inconsistencies could be problematic.

.github/workflows/autoformat.yml

@@ -27,6 +27,7 @@ jobs:
         uses: msys2/setup-msys2@v2
         with:
           install: git mingw-w64-x86_64-clang
+          release: false # Use version from runner images to reduce build times
 
       - name: Disable autocrlf # Messes up everything on Windows since the formatter applies \n
         run: |