Docs to accommodate the deprecation of envTemplate's use of {{.IMAGE_NAME}}

[felixtran39]

Description
Changing the docs to accommodate the deprecation of envTemplate's use of {{.IMAGE_NAME}}. The link to that PR is: #4533

Depends on PR #4533

[codecov]

Codecov Report

Merging #4532 into master will increase coverage by 0.29%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4532      +/-   ##
==========================================
+ Coverage   72.39%   72.69%   +0.29%     
==========================================
  Files         334      335       +1     
  Lines       12992    12971      -21     
==========================================
+ Hits         9406     9429      +23     
+ Misses       2987     2949      -38     
+ Partials      599      593       -6     

Impacted Files	Coverage Δ
pkg/skaffold/schema/latest/config.go	100.00% <ø> (ø)
pkg/skaffold/kubernetes/client.go	0.00% <0.00%> (-40.00%)	⬇️
pkg/skaffold/kubernetes/context/context.go	85.36% <0.00%> (-12.20%)	⬇️
pkg/skaffold/deploy/labels.go	49.36% <0.00%> (-6.59%)	⬇️
pkg/skaffold/deploy/kubectl/labels.go	87.09% <0.00%> (-6.01%)	⬇️
cmd/skaffold/app/cmd/cmd.go	64.96% <0.00%> (-1.46%)	⬇️
pkg/skaffold/deploy/deploy_mux.go	87.80% <0.00%> (-1.33%)	⬇️
pkg/skaffold/runner/new.go	63.93% <0.00%> (-0.59%)	⬇️
pkg/skaffold/build/build.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/flags.go	86.36% <0.00%> (ø)
... and 23 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1110eb1...44ccfa2. Read the comment docs.

[yuwenma]

LGTM!

[briandealwis]

Looks great once #4533 is in.

[briandealwis]

Oh you'll need to make generate-schemas and add those changes in too.

Schema needs to be regenerated.

[briandealwis]

Looks like TestBuild/envTemplate_tagger need to be fixed up?