chore(deps): bump actions/setup-dotnet from 3 to 4 in /.github/workflows (#943)

Bumps [actions/setup-dotnet](https://github.com/actions/setup-dotnet) from 3 to 4.

Author: dependabot[bot]

.github/workflows/ci_codegen.yml

@@ -45,7 +45,7 @@ jobs:
           dafny-version: 4.2.0
 
       - name: Setup .NET Core SDK ${{ matrix.dotnet-version }}
-        uses: actions/setup-dotnet@v3
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: ${{ matrix.dotnet-version }}