Bump acts_as_list from 0.9.15 to 0.9.16

Bumps [acts_as_list](https://github.com/swanandp/acts_as_list) from 0.9.15 to 0.9.16.
- [Release notes](https://github.com/swanandp/acts_as_list/releases)
- [Changelog](https://github.com/swanandp/acts_as_list/blob/master/CHANGELOG.md)
- [Commits](brendon/acts_as_list@v0.9.15...v0.9.16)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

Gemfile.lock

@@ -50,7 +50,7 @@ GEM
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    acts_as_list (0.9.15)
+    acts_as_list (0.9.16)
       activerecord (>= 3.0)
     addressable (2.5.2)
       public_suffix (>= 2.0.2, < 4.0)