Log Message:
pkgtools/pkglint: update to 21.1.3

Changes since 21.1.2:

The entries in doc/CHANGES are checked more strictly, they must always
consist of 4 words (for removed packages) or 6 words (for all other
changes).

Packages that include curses.buildlink3.mk may use all buildlink3
variables with the identifier "curses".  The previous pkglint warnings
had been wrong.

Python packages that directly contain .egg-info in their PLIST files
should include egg.mk instead.  Pkglint can now fix these packages
automatically.