Bump rubyzip from 2.3.0 to 2.3.1

Bumps [rubyzip](https://github.com/rubyzip/rubyzip) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/rubyzip/rubyzip/releases)
- [Changelog](https://github.com/rubyzip/rubyzip/blob/master/Changelog.md)
- [Commits](https://github.com/rubyzip/rubyzip/compare/v2.3.0...v2.3.1)

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

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

Gemfile.lock

@@ -425,7 +425,7 @@ GEM
     ruby-vips (2.1.2)
       ffi (~> 1.12)
     ruby2_keywords (0.0.4)
-    rubyzip (2.3.0)
+    rubyzip (2.3.1)
     sass-rails (6.0.0)
       sassc-rails (~> 2.1, >= 2.1.1)
     sassc (2.4.0)