Version number / news for release 3.12

3.12.0beta2 release

Prep 3.12.0beta1

Version bump for 3.11.2 release

Prep for 3.10.5 release

bump versions for 3.6.6 release

Merge branch '3.10' of github.com:libgeos/geos into 3.10

Update NEWS

3.11 release

3.11.0 release