fix: fix nil pointer issue for skaff lint when encountering skaffold.yaml with no k8s manifests

[aaron-prindle]

No description provided.

[tejal29]

Can you add a unit test for it please.

[codecov]

Codecov Report

Merging #6832 (dbc76c5) into main (290280e) will decrease coverage by 1.34%.
The diff coverage is 64.65%.

@@            Coverage Diff             @@
##             main    #6832      +/-   ##
==========================================
- Coverage   70.48%   69.13%   -1.35%     
==========================================
  Files         515      547      +32     
  Lines       23150    25034    +1884     
==========================================
+ Hits        16317    17307     +990     
- Misses       5776     6566     +790     
- Partials     1057     1161     +104     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/deploy.go	52.00% <ø> (-1.85%)	⬇️
cmd/skaffold/app/cmd/dev.go	84.61% <0.00%> (ø)
cmd/skaffold/app/cmd/flags.go	91.00% <0.00%> (+0.18%)	⬆️
cmd/skaffold/app/cmd/render.go	36.66% <0.00%> (-4.72%)	⬇️
cmd/skaffold/skaffold.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/inspect_tests.go	62.50% <14.28%> (-1.14%)	⬇️
cmd/skaffold/app/cmd/lint.go	42.85% <42.85%> (ø)
cmd/skaffold/app/cmd/find_configs.go	48.88% <50.00%> (+0.24%)	⬆️
cmd/skaffold/app/skaffold.go	76.19% <70.00%> (-8.43%)	⬇️
cmd/skaffold/app/cmd/inspect_build_env.go	65.11% <75.00%> (+6.39%)	⬆️
... and 161 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 b32a1e8...dbc76c5. Read the comment docs.

[aaron-prindle]

Can you add a unit test for it please.

done