Bump undercover from 0.5.0 to 0.6.3

Bumps [undercover](https://github.com/grodowski/undercover) from 0.5.0 to 0.6.3.
- [Release notes](https://github.com/grodowski/undercover/releases)
- [Changelog](https://github.com/grodowski/undercover/blob/master/CHANGELOG.md)
- [Commits](grodowski/undercover@v0.5.0...v0.6.3)

---
updated-dependencies:
- dependency-name: undercover
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Gemfile

@@ -156,7 +156,7 @@ group :test do
   # launch browser when inspecting capybara specs
   gem "launchy"
   gem "timecop"
-  gem "undercover", "~> 0.5.0"
+  gem "undercover", "~> 0.6.3"
   gem "webmock"
 
   gem "rubocop-govuk", require: false

Gemfile.lock

@@ -634,9 +634,9 @@ GEM
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     uber (0.1.0)
-    undercover (0.5.0)
+    undercover (0.6.3)
       bigdecimal
-      imagen (>= 0.1.8)
+      imagen (>= 0.2.0)
       rainbow (>= 2.1, < 4.0)
       rugged (>= 0.27, < 1.8)
     unicode-display_width (2.6.0)
@@ -751,7 +751,7 @@ DEPENDENCIES
   syntax_tree-rbs
   timecop
   tzinfo-data
-  undercover (~> 0.5.0)
+  undercover (~> 0.6.3)
   view_component
   web-console
   webmock