Update paper_trail_manager requirement from ~> 0.5.0 to >= 0.5, < 0.7

Updates the requirements on [paper_trail_manager](https://github.com/igal/paper_trail_manager) to permit the latest version.
- [Release notes](https://github.com/igal/paper_trail_manager/releases)
- [Changelog](https://github.com/fusion94/paper_trail_manager/blob/master/CHANGES.md)
- [Commits](https://github.com/igal/paper_trail_manager/commits/v0.6.0)

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

calagator.gemspec

@@ -37,7 +37,7 @@ Gem::Specification.new do |s|
   s.add_dependency "loofah-activerecord", "~> 1.2"
   s.add_dependency "lucene_query", "0.1"
   s.add_dependency "nokogiri"
-  s.add_dependency "paper_trail_manager", "~> 0.5.0"
+  s.add_dependency "paper_trail_manager", ">= 0.5", "< 0.7"
   s.add_dependency "rack-contrib", "~> 1.0"
   s.add_dependency "rails-observers"
   s.add_dependency "rails_autolink", "~> 1.1"