Bump dalli from 2.7.7 to 2.7.8

Bumps [dalli](https://github.com/petergoldstein/dalli) from 2.7.7 to 2.7.8.
- [Release notes](https://github.com/petergoldstein/dalli/releases)
- [Changelog](https://github.com/petergoldstein/dalli/blob/master/History.md)
- [Commits](petergoldstein/dalli@v2.7.7...v2.7.8)

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

Author: dependabot-support

Gemfile.lock

@@ -79,7 +79,7 @@ GEM
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
     crass (1.0.4)
-    dalli (2.7.7)
+    dalli (2.7.8)
     debug_inspector (0.0.3)
     domain_name (0.5.20170404)
       unf (>= 0.0.5, < 1.0.0)