[Feature] Replace patterns in subject

The subject supports now a DSL-setter to replace specific patterns from the execution output instead of paths only.

/c @AliSoftware @segiddins
I haven't played a lot with dates in Ruby, do `Date#to_s` output generally depend on user settings (like the locale / env vars / LC_LOCALE / …)? Or are they always output in the same format regardless of the locale?

If the output is dependent on locale / user settings, wouldn't it be great to have a convenience method `replace_dates(replacement)` that replaces dates for the current (or any) locale, by dynamically generating the regex to use for the date? Don't know how we could achieve this but it would be awesome to be locale-indépendant that way!