Update dev.yml

.github/workflows/dev.yml

@@ -49,6 +49,7 @@ jobs:
         shell: pwsh
         run: |
           & dotnet workload install maui `
+            --skip-sign-check `
             --from-rollback-file https://aka.ms/dotnet/maui/6.0.300/rc.2.json `
             --source https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-runtime-323bf2dd/nuget/v3/index.json `
             --source https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-emsdk-572aeedc/nuget/v3/index.json `