Log Message:
pkgin: Update to 21.7.0.

## Version 21.7.0 (2021-07-22)

 * Syncronise latest humanize_number() from NetBSD, sizes greater than 64PB
   are now printed correctly.
 * Regenerate for autoconf-2.71 and fix "make distcheck".
 * Fix inconsistent output when using globs.
 * Fix out-of-srcdir builds.
 * Improve fetch failure error messages.
 * Update documentation to reflect IRC migration to Libera.