Change 'allowed-tags' rule parameter from a comma-separated list to a regular expression

[Bertk]

@racodond We use SpecFlow and want to use references in feature tags to synchronize TFS work items or test cases (https://www.youtube.com/watch?v=uhZH81sMMfs).
I implemented a plugin already with the rule "allowed-composite-tag" (see https://github.com/Bertk/sonar-gherkin-custom-rules-plugin/).
Can this rule be added to the SonarQube Gherkin plugin?
The current solution of a separate plugin with only one single rule is somehow overdone.

see #58

[racodond]

@Bertk: My apologies for the long long long delay... Version 1.6 has just been released: https://github.com/racodond/sonar-gherkin-plugin/releases/tag/1.6

[Bertk]

@racodond Thank you 🎄