mail/mu: Update to 1.14.1

Switch the bundled cli11 to devel/cli11.
Since databases/xapian-core has been updated to 2.0.0, switch from
xapian-core to xapian-core14.
Switch from USES=compiler:c++17-lang to c++20-lang.
Regenerate files/patch-mu4e_meson.build.

https://github.com/djcb/mu/releases/tag/v1.14.0
https://github.com/djcb/mu/releases/tag/v1.14.1

PR: 295350
Co-authored-by: Herbert J. Skuhra <herbert@gojira.at>
Approved by: rwn@mailo.com (maintainer, timeout)
Approved by: fluffy (mentor)