inject-core: Cross-build for Scala 2.13
inject-core: Cross-build for Scala 2.13

Problem

inject-core is not cross-built for Scala 2.13.

Solution

Update inject-core module to cross-build for Scala 2.13 using new SBT
settings.

Result

inject-core is cross-built for Scala 2.13.

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

Differential Revision: https://phabricator.twitter.biz/D543138

twitter/finatra,twitter/finatra,twitter/finatra