fix: Gemfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-THOR-10843853

Author: snyk-bot

Gemfile

@@ -143,7 +143,7 @@ gem 'syntax_suggest'
 gem 'tempfile'
 gem 'terminal-table'
 gem 'test-unit'
-gem 'thor'
+gem 'thor', '>= 1.4.0'
 gem 'time'
 gem 'timeout'
 gem 'tmpdir'