protobufCodeGenPlugins strips everything after colon in Windows filenames

[ejona86]

Say you have something like:

protobufCodeGenPlugins = ["my-plugin:$buildDir/some/path"]

If buildDir on Windows starts with C:, the command passed to protoc will be:

--plugin=protoc-gen-my-plugin=C

It seems that some it.split(":") should be it.split(":", 2) in order to avoid stripping the rest of the path, but I had trouble testing the change to confirm.