Check .NET formatting instead of applying it in CI

.gitea/workflows/build-test.yml

@@ -23,7 +23,7 @@ jobs:
         run: dotnet tool restore
 
       - name: Check formatting
-        run: dotnet csharpier format .
+        run: dotnet csharpier check .
 
       - name: Build
         run: dotnet build
@@ -51,4 +51,4 @@ jobs:
       - name: Test
         run: npm test
         env:
-          TZ: UTC
+          TZ: UTC