[ANN] ppx_regexp 0.2.0 and 0.3.0

@c-cube I completely agree. My remark was about getting the best of both worlds: Familiar/terse pcre syntax with ppx_regexp, which desugars to tyre/re combinators to get good composition. Just like Re_* modules.

@paurkedal Yes, exactly. You could probably reuse re’s parser.