Log message:
Pullup ticket #5247 - requested by sevan
pkgtools/pkglint: bugfix

Revisions pulled up:
- pkgtools/pkglint/Makefile                                     1.513
- pkgtools/pkglint/files/vardefs.go                             1.23

---
   Module Name:    pkgsrc
   Committed By:   rillig
   Date:           Wed Apr  5 19:17:19 UTC 2017

   Modified Files:
           pkgsrc/pkgtools/pkglint: Makefile
           pkgsrc/pkgtools/pkglint/files: vardefs.go

   Log message:
   Updated pkglint to 5.4.20.

   Changes since 5.4.19:
   * Updated allowed Python versions to include py36.