extended [allowRegex] parameter for unused-parameter and unused-receiver rules

[comdiv]

Impl for #613 feature-request

Now can provide custom regexes for unused-parameter and unused-receiver to allow names matching some regex, no just _ itself (does'nt break default behavior)

[rule.unused-parameter]
     Arguments = [ { allowRegex = "^_" } ]

[rule.unused-receiver]
     Arguments = [ { allowRegex = "^_" } ]

[chavacava]

Hi @comdiv, thanks for the PR. Please open an issue before opening a PR.
Opening an issue will let us discuss on the subject and find the right way to cope with the request.

[comdiv]

Sorry, i thought it was open early - it's fix for old issue #613 - what exatly i have to do?