Update version v1.19 -> v1.20 (googleapis#883)

Update discovery documents and generated code

automatically_generated_update

Update discovery documents and generated code

automatically_generated_update

Update discovery documents and generated code

automatically_generated_update

Update discovery documents and generated code

automatically_generated_update

Fix nuget restore in GeneratedLibraries.proj (googleapis#796)

Update discovery documents and generated code

automatically_generated_update

Updated version to 1.14.0 for support and generated libraries

Update discovery documents and generated code

automatically_generated_update

Update discovery documents and generated code

automatically_generated_update