ci: Add pre-release action to prepare release branch #1432

Job	Run time
Build Distribution Bundle	34s
Test Jest (16.x)	27s
Test Jest (17.x)	37s
Test Jest (18.x)	26s
Test Jest (19.x)	30s
Test Jest (20.x)	29s
Get Bundle Size from Master	7s
Get Bundle Size from Current Branch	25s
Core Tests / Core SDK Tests	1m 15s
Calculate Bundled Diff / Calculate Bundle Size Difference	9s
Generate Report	1s
Test Stub	38s
Integration Tests: webpack Common JS / webpack CJS Test	1m 4s
Integration Tests: Rollup Common JS / Rollup CJS Test	1m 7s
Integration Tests: Browserfy Common JS / Browserfy CJS Test	1m 0s
Integration Tests: Rollup Module JS / Rollup Module Test	1m 0s
Integration Tests: webpack Module JS / webpack Module Test	1m 4s
Integration Tests: Require JS / Require JS Test	43s
Save PR Number for Dependabot Automerge / Save PR Number for Dependabot Automerge	0s
	11m 36s

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