Bump terser from 1.1.12 to 1.1.13

Bumps [terser](https://github.com/ahorek/terser-ruby) from 1.1.12 to 1.1.13.
- [Release notes](https://github.com/ahorek/terser-ruby/releases)
- [Changelog](https://github.com/ahorek/terser-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ahorek/terser-ruby/compare/1.1.12...1.1.13)

---
updated-dependencies:
- dependency-name: terser
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -489,7 +489,7 @@ GEM
     telegraf (2.1.1)
       influxdb
     temple (0.8.2)
-    terser (1.1.12)
+    terser (1.1.13)
       execjs (>= 0.3.0, < 3)
     thor (1.2.1)
     tilt (2.0.11)