Bump capybara from 3.14.0 to 3.15.0

Bumps [capybara](https://github.com/teamcapybara/capybara) from 3.14.0 to 3.15.0.
- [Release notes](https://github.com/teamcapybara/capybara/releases)
- [Changelog](https://github.com/teamcapybara/capybara/blob/master/History.md)
- [Commits](teamcapybara/capybara@3.14.0...3.15.0)

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

Gemfile.lock

@@ -52,7 +52,7 @@ GEM
     awesome_print (1.8.0)
     builder (3.2.3)
     byebug (11.0.0)
-    capybara (3.14.0)
+    capybara (3.15.0)
       addressable
       mini_mime (>= 0.1.3)
       nokogiri (~> 1.8)