Fix golangci linter warnings

[marcofranssen]

To improve code quality it would be great if we can resolve the linter warnings.

Use

make lint

to identify the findings

use

make test

to test your refactorings didn't break anything.

[github-actions]

@marcofranssen this issue was automatically closed because it did not follow the issue template

[cw-Guo]

@marcofranssen just want to let you know that this issue was closed automatically.

[u5surf]

@marcofranssen Hi, I would like to work on this issue.
At first, I've checked make lint, I found some issues following that

93 issues:
* dupl: 24
* goconst: 6
* gocyclo: 12
* lll: 50
* staticcheck: 1
make: *** [lint] Error 1

Can I split some PRs each rules?

[marcofranssen]

@u5surf sure you can. Please note I have 2 branches already:

• Fix cyclomatic complexity linter warnings #1708
• Resolve long line length linter warnings #1710

For gocyclo, I didn't touch the fluentd folders, so you could take those if you want.

[u5surf]

Another issue like following had been encounted while executing make lint.

% make test
# golang.org/x/tools/internal/tokeninternal

o:64:9: invalid array length -delta * delta (constant -256 of type int64)
make: *** [/Users/u5surf/fluent-operator/bin/controller-gen] Error 1

It seems that the latest golang has issue in x/tools

golang/go#74462

[marcofranssen]

Run it on top of #1702 and start fixing from there ;)