chore: clean up example project deps

[ericzzzzzzz]

I've been seeing

go: github.com/GoogleContainerTools/skaffold/examples/grpc-e2e-tests/service@v0.0.0-00010101000000-000000000000: invalid version: unknown revision 000000000000
go: github.com/GoogleContainerTools/skaffold/examples/grpc-e2e-tests/service@v0.0.0-00010101000000-000000000000: invalid version: unknown revision 000000000000

every time I open skaffold project with IntelliJ, this doesn't seem doing anything, but it's very annoying.

[codecov]

Codecov Report

Attention: 295 lines in your changes are missing coverage. Please review.

Comparison is base (290280e) 70.48% compared to head (50958c6) 63.65%.
Report is 1077 commits behind head on main.

Files	Patch %	Lines
cmd/skaffold/app/cmd/exec.go	16.32%	40 Missing and 1 partial ⚠️
cmd/skaffold/app/cmd/filter.go	47.27%	22 Missing and 7 partials ⚠️
cmd/skaffold/app/cmd/lsp.go	28.12%	23 Missing ⚠️
cmd/skaffold/app/cmd/verify.go	23.33%	23 Missing ⚠️
cmd/skaffold/app/cmd/fix.go	51.16%	17 Missing and 4 partials ⚠️
cmd/skaffold/app/cmd/inspect_job_manifest_paths.go	60.00%	15 Missing and 1 partial ⚠️
cmd/skaffold/app/cmd/inspect_namespaces.go	50.00%	13 Missing and 1 partial ⚠️
...md/skaffold/app/cmd/inspect_config_dependencies.go	45.83%	12 Missing and 1 partial ⚠️
cmd/skaffold/app/cmd/lint.go	42.85%	12 Missing ⚠️
cmd/skaffold/app/cmd/inspect_build_env.go	60.71%	11 Missing ⚠️
... and 21 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9216      +/-   ##
==========================================
- Coverage   70.48%   63.65%   -6.84%     
==========================================
  Files         515      632     +117     
  Lines       23150    32546    +9396     
==========================================
+ Hits        16317    20716    +4399     
- Misses       5776    10237    +4461     
- Partials     1057     1593     +536     

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