Quote step names
Quote step names

This works around an export-to-YAML bug tracked by (internal)
https://mseng.visualstudio.com/VSOnline/_workitems/edit/1289423.

sean-gilliam/msbuild,Microsoft/msbuild,Microsoft/msbuild,rainersigwald/msbuild,mono/msbuild,chipitsine/msbuild,jeffkl/msbuild,cdmihai/msbuild,AndyGerlicher/msbuild,jeffkl/msbuild,mono/msbuild,rainersigwald/msbuild,AndyGerlicher/msbuild,jeffkl/msbuild,chipitsine/msbuild,mono/msbuild,jeffkl/msbuild,sean-gilliam/msbuild,rainersigwald/msbuild,chipitsine/msbuild,Microsoft/msbuild,chipitsine/msbuild,sean-gilliam/msbuild,mono/msbuild,Microsoft/msbuild,cdmihai/msbuild,rainersigwald/msbuild,sean-gilliam/msbuild,cdmihai/msbuild,cdmihai/msbuild,AndyGerlicher/msbuild,AndyGerlicher/msbuild