Add dotnet 2.1.300, remove dotnet 2.1.201 [#157967601]
Add dotnet 2.1.300, remove dotnet 2.1.201 [#157967601]

Signed-off-by: Andrew Meyer <8f92422f5861fc9f31873f75dd770facd670512b@pivotal.io>

cloudfoundry-community/asp.net5-buildpack