archivers/libarchive: Update to 3.6.0

Backport upstream commits 52efa50c69653029687bfc545703b7340b7a51e2 and
1271f775dc917798ad7d03c3b3bd66bacad03603 for security fixes in
RAR filter, suggested by Tod Jackson

Changelog: https://github.com/libarchive/libarchive/releases/tag/v3.6.0

PR: 262069
Approved by: glewis (maintainer timeout, 2+ weeks)