Log Message:
pkgtools/pkglint: update to 20.1.2

Changes since 20.1.1:

Ensure that relative paths to other packages have the canonical form
../../category/package.

Add notes about pathname patters that mention ${WRKSRC} even though they
are already defined to be relative to WRKSRC.

Fix check for redundantly added categories. The check had previously
reported that the included file would be redundant, which was wrong.
It's always the including file that provides the redundancy.