Log Message:
devel/py-maturin: tool.mk: Require recent version

At least devel/py-rpds-py fails to build with somewhat older maturin,
but this is hard to figure out from reading upstream NEWS.  And,
py-rpds-py upstream simply says it needs maturin, wihtout a version
requirement.

While 1.8.3 is surely a more strict requirement than necessary, it's
difficult to determine what the real requirements are.  When maturin
is used as a tool, require >=1.8.3 (the current version).  This choice
favors avoiding unknown problems with the downside that some
people:(but only those that have pkgsrc installations with
persistently outdated packages) will now have to update maturin.

This commit does not intend to establish a rule that the minimum
version should be increased on every update.