Port pcre dependency to pcre2

[Cropi]

Upstream stopped the support for the old 'pcre' package. See https://www.pcre.org/ It only supports the new 'pcre2' version, we should replace the current pcre with the newer pcre2.

I know that for various reasons it's not recommended to use regex but some years ago it has been enabled and shipped in Fedora, so we would like to further maintain it. Fixes #366

Let me know what you think. If you feel like I can add a configuration option be able to specify which version of pcre you want to compile with. Thanks.

[Cropi]

Some checks might complain about the presence of pcre2 but that is expected.