devel/got: update to 0.71

User-visible changes:

• implicitly unstage changes when staging the reverse of a staged diff
• add one-line output mode to got log with -s flag
• rename the former got log -s (search) flag to got log -S
• make it possible to match committed patches with got log -p -S pattern
• make got log -S match author name and commit ID, like tog search does
• tog: add key bindings for half-page scroll
• add horizontal scrolling to tog diff, blame, and log views
• show last-modified date in the "tog ref" view if 'm' is pressed