[release/6.0.2xx] Backport CODEOWNERS (#61)

So we get appropriate notifications. Extension of #54.

.github/CODEOWNERS

@@ -0,0 +1,15 @@
+# Users referenced in this file will automatically be requested as reviewers for PRs that modify the given paths.
+# See https://help.github.com/articles/about-code-owners/
+
+*                                                                                 @Pilchie
+/global.json                                                                      @dotnet/aspnet-build
+/azure-pipelines.yml                                                              @dotnet/aspnet-build
+/NuGet.config                                                                     @dotnet/aspnet-build
+/.vscode/                                                                         @dotnet/aspnet-build @TanayParikh
+/.devcontainer/                                                                   @dotnet/aspnet-build @TanayParikh
+/.github/                                                                         @dotnet/aspnet-build
+/src/                                                                             @dotnet/aspnet-blazor-eng
+/eng/                                                                             @dotnet/aspnet-build
+/eng/common/                                                                      @dotnet-maestro-bot
+/eng/Versions.props                                                               @dotnet-maestro-bot @dotnet/aspnet-build
+/eng/Version.Details.xml                                                          @dotnet-maestro-bot @dotnet/aspnet-build