Fix part of lint/go errors (goimports, staticcheck, gosimple)

[karamaru-alpha]

What this PR does / why we need it:

Fix part of errors which make lint/go returns(goimports, staticcheck, gosimple).

List of remaining errors

• goimports
• gosimple
• staticcheck
• deadcode
• errcheck
• goerr113
• typecheck
• ineffassign
• misspell, depguard, unconvert Fix part of lint/go errors (misspell, depguard, unconvert) #4621

Which issue(s) this PR fixes:

part of #4566

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

Attention: 12 lines in your changes are missing coverage. Please review.

Comparison is base (4ed62fb) 29.98% compared to head (d3086a0) 29.97%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4622      +/-   ##
==========================================
- Coverage   29.98%   29.97%   -0.02%     
==========================================
  Files         221      221              
  Lines       25955    25939      -16     
==========================================
- Hits         7783     7775       -8     
+ Misses      17523    17518       -5     
+ Partials      649      646       -3     

Files	Coverage Δ
pkg/model/application_live_state.go	41.17% <ø> (-0.86%)	⬇️
.../app/piped/platformprovider/terraform/terraform.go	10.48% <0.00%> (+0.19%)	⬆️
pkg/model/project.go	62.58% <42.85%> (+0.42%)	⬆️

... and 3 files with indirect coverage changes

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[kentakozuka]

Thanks!!!

[kentakozuka]

Found some nits

[kentakozuka]

Suggested change

	if err := p.Github.Encrypt(encrypter); err != nil {
	return err
	}
	return nil
	return p.Github.Encrypt(encrypter)

[karamaru-alpha]

Thanks for the review!
Fix return error by function

[kentakozuka]

Suggested change

	if err := p.Github.Decrypt(decrypter); err != nil {
	return err
	}
	return nil
	return p.Github.Decrypt(decrypter)

[karamaru-alpha]

I found still remaining errors by gosimple and corrected.
Thank you for your confirmation.
Fix lint/go errors (gosimple)

[kentakozuka]

👍