v0.20.2: Fix autoscale on workflow_job with labels

CAUTION: If you're using the Helm chart, beware to review changes to CRDs and do manually upgrade CRDs! Helm installs CRDs only on installing a chart. It doesn't automatically upgrade CRDs. Otherwise, you end up with troubles like #427, #467, and #468. Please refer to the UPGRADING docs for the latest process.

This release includes a fix, #850 and #852 for the issue #851 that autoscaling on workflow_job events doesn't work as expected when runner labels are used. A lot of thanks goes to @artificial-aidan and @peimanja for providing detailed issue reports in #851 and #819 (comment), and also @blz-ea and @artificial-aidan for contributing the fix and the test cases!