build: bump activesupport from 6.0.1 to 6.0.2 in /docs

Bumps [activesupport](https://github.com/rails/rails) from 6.0.1 to 6.0.2.
- [Release notes](https://github.com/rails/rails/releases)
- [Changelog](https://github.com/rails/rails/blob/v6.0.2/activesupport/CHANGELOG.md)
- [Commits](https://github.com/rails/rails/compare/v6.0.1...v6.0.2

)

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

docs/Gemfile.lock

 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.0.1)
+    activesupport (6.0.2)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)