Small docs tweak to make it clear version is optional
Small docs tweak to make it clear version is optional

google/google-api-objectivec-client-for-rest,google/google-api-objectivec-client-for-rest,google/google-api-objectivec-client-for-rest,google/google-api-objectivec-client-for-rest,dougbeal/google-api-swift-client-for-rest,google/google-api-objectivec-client-for-rest,dougbeal/google-api-swift-client-for-rest,dougbeal/google-api-swift-client-for-rest,dougbeal/google-api-swift-client-for-rest