git-delta: update to 0.12.1.

What's Changed

    Make git include colors in output going to delta by @dandavison in #966
    Clarify language: "in front of" → "before" by @waldyrious in #967
    Fix parsing for .properties files with - in path by @jdpopkin in #975
    Support CSI sequences other than SGR by @yoichi in #976
    Enable commit links for GitLab by @jwarlander in #972
    Fall back to plain diff when process substitution is used by @th1000s in #978
    Include information about GIT_PAGER in manual by @katylava in #991
    Use assets API from bat library instead of vendored code by @dandavison in #903
    Calling process: Query more parents, disable full scan by @th1000s in #984
    Run in diff mode iff two positional arguments are supplied by @dandavison in #995

(wiz)