refactor: Update CI workflow to support runpod>= versioning

[deanq]

Changes:

• Update grep pattern from runpod~= to runpod>=
• Replace major.minor range logic with semantic version comparison
• Add validation for current_version extraction
• Update sed replacement to maintain >= operator
• Workflow now triggers on any version increase (patch, minor, major)

Previously, the workflow only updated for major.minor changes due to ~= (compatible release) constraint. Now with >=, all new releases are honored.