Update rake requirement from ~> 12.2 to ~> 13.0

Updates the requirements on rake to permit the latest version.

Changelog

Sourced from rake's changelog.

=== 13.0.6

• Additional fix for #389 Pull request #390 by hsbt

=== 13.0.5

• Fixed the regression of #388 Pull request #389 by hsbt

=== 13.0.4

• Fix rake test loader swallowing useful error information. Pull request #367 by deivid-rodriguez
• Add -C/--directory option the same as GNU make. Pull request #376 by nobu

=== 13.0.3

• Fix breaking change of execution order on TestTask. Pull request #368 by ysakasin

=== 13.0.2

==== Enhancements

• Fix tests to work with current FileUtils Pull Request #358 by jeremyevans
• Simplify default rake test loader Pull Request #357 by deivid-rodriguez
• Update rdoc Pull Request #366 by bahasalien
• Update broken links to rake articles from Avdi in README Pull Request #360 by svl7

=== 13.0.1

==== Bug fixes

• Fixed bug: Reenabled task raises previous exception on second invokation Pull Request #271 by thorsteneckel
• Fix an incorrectly resolved arg pattern Pull Request #327 by mjbellantoni

=== 13.0.0

==== Enhancements

• Follows recent changes on keyword arguments in ruby 2.7. Pull Request #326 by nobu

... (truncated)

Commits

• 5c60da8 Bump up Rake-13.0.6
• 73d4099 Merge pull request #390 from ruby/fix-388-again
• 63aacb6 Added Rake namespace explicitly
• 29a3949 Bump version to v13.0.5
• 3a95f4c Merge pull request #389 from ruby/fix-388
• 85c55b4 Fixed the regression of #388
• 72ac796 History for rake-13.0.4
• b20de78 Bump version to 13.0.4
• a07e637 Merge pull request #386 from ruby/cleanup
• 0acc575 Use require_relative to specify release version
• Additional commits viewable in compare view