Allow Innovative upgrades to be skipped during upgrade

[prafull01]

Fixes: #1088

1. Allow Innovative upgrades to be skipped during upgrade process.
2. Added e2e tests to for the same.

[Copilot]

Pull Request Overview

This pull request enables users to skip innovative upgrades during the upgrade process and adds new end‑to‑end tests along with supporting functions and test cases to validate the behavior.

• Adds a new e2e test to verify that innovative upgrades can be skipped.
• Introduces helper functions (getReleaseType, generateReleases, getNextReleases, getPreviousReleases) in the update package for upgrade/rollback logic.
• Updates both the production code and corresponding tests and internal helper definitions.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
e2e/upgrades/upgrades_test.go	Adds a new test for skipping innovative upgrades during major version upgrades.
pkg/update/update_cockroach_version_common.go	Introduces new functions and modifies upgrade/rollback logic to support skipping innovative releases.
pkg/update/update_cockroach_version_common_test.go	Updates and renames tests to match new function names and adds tests for new release functions.
pkg/update/internal.go	Adds a new ReleaseType type and related constant definitions.
pkg/update/update_cockroach_version.go	Refactors calls to use the new upgrade/rollback functions.

Comments suppressed due to low confidence (2)

pkg/update/update_cockroach_version_common.go:278

• [nitpick] Consider caching the formatted current version (e.g. using a variable) to avoid recomputing the same string in the loop, which could improve clarity and minor performance.

nextPossibleRelease := getNextReleases(fmt.Sprintf("%d.%d", currentVersion.Major(), currentVersion.Minor()))

pkg/update/update_cockroach_version_common_test.go:115

• [nitpick] Consider using require.Equal(test.result, isMajorUpgradeAllowed(test.wantVersion, test.currentVersion)) for clearer assertions and more descriptive error messages in tests.

require.True(t, isMajorUpgradeAllowed(test.wantVersion, test.currentVersion) == test.result, "isMajorUpgradeAllowed test failed")