Bump rake in /sources_non_forked/vim-multiple-cursors (amix#565)

Bumps [rake](https://github.com/ruby/rake) from 10.4.2 to 12.3.3.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v10.4.2...v12.3.3)

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

Author: dependabot[bot]

sources_non_forked/vim-multiple-cursors/Gemfile.lock

@@ -2,7 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     diff-lcs (1.2.5)
-    rake (10.4.2)
+    rake (12.3.3)
     rspec (3.4.0)
       rspec-core (~> 3.4.0)
       rspec-expectations (~> 3.4.0)