[soci-users] GitFlow dropped and default branch changed to master

[Mateusz Loskot]

(CC: soci-user and soci-develop)

Folks,

Following recent request and discussion to simplify the Git(Hub) workflow,
details at https://github.com/SOCI/soci/issues/305,
GitFlow has been dropped and the new branchnig model is based
on SVN-like traditional branches:
- master renamed to release/3.2; it's the maintenance branch for SOCI 3.x
- develop renamed to master; master is the main development branch
- develop deleted

Best regards,