Bump rake from 13.0.3 to 13.0.6 (#622)

Author: dependabot[bot]

Gemfile.lock

@@ -83,7 +83,7 @@ GEM
     netrc (0.11.0)
     open4 (1.3.4)
     public_suffix (4.0.6)
-    rake (13.0.3)
+    rake (13.0.6)
     redcarpet (3.5.1)
     rouge (3.24.0)
     ruby-macho (1.4.0)