*/*: update dependency on devel/py-lxml to devel/py-lxml5

www/py-beautifulsoup has switched dependency on devel/py-lxml to
devel/py-lxml5.

Ports which directly or indirectly depends on both
www/py-beautifulsoup and devel/py-lxml must also switch their
dependencies on devel/py-lxml to devel/py-lxml5 to avoid conflicts.

PR: 288047
Approved by: portmgr (chase dependency change)