httpAnnotations/jsonAnnotations: Cross-build for 2.13
httpAnnotations/jsonAnnotations: Cross-build for 2.13

Problem

httpAnnotations and jsonAnnotations were not cross-built for Scala 2.13.

Solution

Add SBT settings and rules to enable cross-building and cross build
these two modules.

Result

httpAnnotations and jsonAnnotations are cross-built for Scala 2.13.

Signed-off-by: Yufan Gong <yufang@twitter.com>

Differential Revision: https://phabricator.twitter.biz/D541790

twitter/finatra,twitter/finatra,twitter/finatra