Address PR review suggestions:
- Added restore-keys fallback for Helm cache in all 3 jobs (unit_tests,
integration_tests, helm) enabling graceful version migration on cache miss.
- Added HELM_VERSION: "v3.16.4" to the workflow global environment to enable DRY key construction for caching.
- Introduced actions/cache@v3 (id: helm-cache) before the "Install Helm CLI" step in the unit_tests, integration_tests, and helm jobs to cache the Helm binary and reduce per-job download overhead (~15-25 seconds per job).
- Made the "Install Helm CLI" step conditional on cache misses by using steps.helm-cache.outputs.cache-hit != 'true' in all three jobs.
- Removed the hardcoded HELM_VERSION from the install script; it now relies on the HELM_VERSION environment variable.
- Preserved checksum verification on cache miss to maintain integrity of the cached binary.
ISSUES CLOSED: #10033
HAL9000