ci: add pre-main workflow for tests and linting

[sebrandon1]

Quality of life improvements.

I added a couple more make paths and added some automatic testing and linting for pull requests.

One of the biggest changes is that I had to migrate the existing .golangci.yml to v2.

CI/CD and Linting Workflow Enhancements:

• Added a new GitHub Actions workflow (.github/workflows/pre-main.yml) to automatically run Go linting (golangci-lint), shell script formatting (shfmt), and tests on pull requests and pushes to the main branch.
• Added lint, golangci-lint, and shfmt targets to the Makefile for easier local linting and formatting of Go and shell scripts.

Linting Configuration Improvements:

• Overhauled the .golangci.yml configuration: switched to version: "2", enabled and fine-tuned a set of linters (including errorlint, gocyclo, gosec, loggercheck, etc.), improved depguard and revive rules, and added exclusions and formatters for better code quality and maintainability. [1] [2] [3]

Code Quality and Consistency Fixes:

• Removed unnecessary break statements after append operations in addon-tools/helm-convert/convert/expectedvaluesfinder.go for cleaner code. [1] [2]
• Improved error message consistency and clarity in pkg/compare/correlator.go.
• Fixed a minor bug in pkg/compare/compare.go by using the correct IOStreams fields.
• Improved test client setup logic in pkg/compare/compare_test.go for clarity and correctness.
• Fixed template execution in pkg/compare/referenceV1.go to use the correct method.
• Corrected method invocation in pkg/compare/referenceV2.go for processing manifest paths.

[openshift-ci]

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[lack]

I love the change, and I'm all for moving golangci-lint up to v2; but now we have to update prow to match :)

In fact, maybe with the github actions in place, the prow checks are unneeded? Let's remove them if they are truly redundant, as github actions are generally easier to manage.

[sebrandon1]

@lack I opened a PR here to remove it from prow: openshift/release#72623

[sebrandon1]

@lack I've rebased the dependent PR (openshift/release#72623) to resolve the merge conflicts. Once that PR gets merged, the prow checks here should pass and we can proceed with merging this one.

[sebrandon1]

/retest

[openshift-ci]

@sebrandon1: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/golint	92cbbec	link	true	/test golint
ci/prow/unit	92cbbec	link	true	/test unit

Full PR test history. Your PR dashboard.

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