cmark.ex

12f45304 - Bump actions/cache from 2.1.5 to 2.1.6

Bump actions/cache from 2.1.5 to 2.1.6 Bumps [actions/cache](https://github.com/actions/cache) from 2.1.5 to 2.1.6. - [Release notes](https://github.com/actions/cache/releases) - [Commits](https://github.com/actions/cache/compare/v2.1.5...v2.1.6) Signed-off-by: dependabot[bot] <support@github.com>