add support for "registry-mirrors" and "insecure-registries" to buildkit

[AntaresS]

- What I did

• update vendor with the recent patch from buildkit resolver: add config support for mirrors/plainhttp buildkit#612
• integrated with moby side where buildkit is being invoked.
  • pass registry-mirror and insecure-registries fields from daemon.json to buildkit in order to make use.
  • supports live reloading when daemon.json file changes.

- How I did it

- How to verify it

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[AntaresS]

@tonistiigi ptal when you have a chance

[codecov]

Codecov Report

Merging #37852 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #37852      +/-   ##
==========================================
- Coverage   36.12%   36.12%   -0.01%     
==========================================
  Files         610      610              
  Lines       45083    45114      +31     
==========================================
+ Hits        16288    16296       +8     
- Misses      26555    26580      +25     
+ Partials     2240     2238       -2

[AntaresS]

ping @tiborvass @tonistiigi

[tiborvass]

nit: unneeded whitespace

[AntaresS]

👍

[tiborvass]

this is going to panic if there is no //, which according to https://github.com/moby/moby/blob/master/registry/service_v2.go#L15 could happen.

[dmcgowan]

Cleaner to use strings.Index, maybe like

if idx := strings.Index(v, "://"); idx > 0 {
        v = v[idx+3:]
}

[dmcgowan]

Does this need to get set if the mirror prefix is "http://"?

[AntaresS]

@dmcgowan Ah I think I the "http://" prefix must be trimmed here as well. Otherwise, buildkit will add an extra prefix.

[dmcgowan]

Is http:// not valid in configuration?

[AntaresS]

OK. Actually I just learned it is also valid 😅

[AntaresS]

Added a trimming for that as well

[dmcgowan]

LGTM

[AntaresS]

@tiborvass @dmcgowan updated the PR based on the comments. Ptal when you have time.

[tiborvass]

LGTM