v0.12.1

Changelog

4292783 build: make custom_build play more nicely with local registries. Fixes #2928 (#2929)
467f191 build: print docker pull status incrementally (#2920)
543a8ec bump to v0.12.0 (#2916)
9d575c1 dockercompose: don't run docker-compose up in parallel. Fixes issue #2871 (#2932)
eb5b455 k8s: entrypoint override shouldn't affect container args. Fixes issue #2918 (#2933)
92f81e8 k8swatch: fix flaky pod watch test (#2917)
50fa49a tiltfile: add docker_build(extra_tag=...). Fixes issue #2839 (#2931)
b2054d3 tiltfile: add encode_yaml and encode_json (#2926)
0a968ad tiltfile: docker_build(secret=). Fixes issue #2563 (#2937)
1e9f748 tiltfile: enable recursion (#2930)
de26e99 tiltfile: fix arg metrics for builtins from starkit extensions (#2941)
db5476b tiltfile: implement extension for Tilt extensions (#2924)
61f460a tiltfile: move json and yaml to extension (#2922)
7e10d4b tiltile: ability to load extensions (#2927)
9b4f04c vendor: buildkit secret provider (#2936)
ece4be2 vendor: units library for printing buildkit progress (#2921)
59de82a web: fix a width bug in the new HUD layout grid (#2934)