Specify just the MAJOR.MINOR components to `cmake_minimum_required()`.
Specify just the MAJOR.MINOR components to `cmake_minimum_required()`.

Change-Id: I3c568a5f4892803e154fe365739bff8f5050fcfc
Reviewed-on: https://code-review.googlesource.com/c/re2/+/60791
Reviewed-by: Paul Wankadia <62d4e38bb1380f055ec4b899baa75e52af09c5f7@google.com>
Reviewed-by: Perry Lorier <d2756efe887c28699f4587ef278926ee3b3bfae5@google.com>

google/re2,google/re2,google/re2,google/re2,google/re2