Add Swift 6.1.1 and 6.1.2

[Aaron-Ritter]

Is your feature request related to a problem? Please describe.
6.1.1 and 6.1.2 are released, but I get the workflow error Version "6.1.1" is not available

Describe the solution you'd like
Add 6.1.1 and 6.1.2.

[Aaron-Ritter]

@fwal I understand that adding the versions makes sense from a tested perspective. But it blocks us usually a few weeks or some times months if we want to make sure to use a recent, pinned version. #745 would allow us to skip the version check.