Swift has a longstanding bug where a framework and a type cannot be named the
same. We have somehow managed to not run into this, but it now seems to be
hitting us.

Since this is a breaking change, this starts the road for SDK 3.0.

This makes it possible to compile the SDK with Xcode 10 and 11. The problem is
that the Google SDK (used for sign-in) is compiled with Xcode 11. This avoids
the issue.

People run these in their own checkout and will run into problems because
tagging will fail.