Update rgl requirement from ~> 0.5.3 to >= 0.5.3, < 0.7.0

Updates the requirements on [rgl](https://github.com/monora/rgl) to permit the latest version.
- [Release notes](https://github.com/monora/rgl/releases)
- [Changelog](https://github.com/monora/rgl/blob/master/ChangeLog)
- [Commits](monora/rgl@v0.5.3...v0.5.8)

---
updated-dependencies:
- dependency-name: rgl
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

aws_security_viz.gemspec

@@ -30,7 +30,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'graphviz', '~> 1.1', '>= 1.1.0'
   s.add_runtime_dependency 'optimist', '>= 3.0', '< 3.3'
   s.add_runtime_dependency 'organic_hash', '~> 1.0', '>= 1.0.2'
-  s.add_runtime_dependency 'rgl', '~> 0.5.3'
+  s.add_runtime_dependency 'rgl', '>= 0.5.3', '< 0.7.0'
   s.add_runtime_dependency 'webrick', '>= 1.8.1', '< 1.10.0'
   s.add_runtime_dependency 'aws-sdk-ec2', '>= 1.65', '< 1.499'