Bump scala version to 2.12.13 in workflows
Bump scala version to 2.12.13 in workflows

Problem/Solution

We've updated the supported scala version in the sbt files
lets follow up with the CI workflows. Util was already done
in the first update.

Differential Revision: https://phabricator.twitter.biz/D635494

twitter/scrooge,twitter/scrooge,twitter/scrooge,twitter/scrooge