Replace blocked label with workflow::blocked

## Summary

To assist in reporting and reduce duplicate labels, we will be conslidating ~"blocked [deprecated in favor of workflow : : blocked]" and ~"workflow::blocked". To do this, we will need to rename both labels to reduce the amount of change to [Org Boards]() and email notifications triggered by GitLab Bot. 

Currently the ~"workflow::blocked" label is used less than the ~"blocked [deprecated in favor of workflow : : blocked]" so we will rename ~"blocked [deprecated in favor of workflow : : blocked]" to ~"workflow::blocked" and migrate the existing ~"workflow::blocked" to the new label.

| Type of Resource | ~"workflow::blocked" Count | ~"blocked [deprecated in favor of workflow : : blocked]" Count |
| ------ | ------ | ------ |
| Boards | 10 | 16 |
| Issues | [23](https://gitlab.com/groups/gitlab-org/-/issues?scope=all&utf8=%E2%9C%93&state=all&label_name[]=workflow%3A%3Ablocked) | [164](https://gitlab.com/groups/gitlab-org/-/issues?scope=all&utf8=✓&state=all&label_name[]=blocked%20%5Bdeprecated%20in%20favor%20of%20workflow%20%3A%20%3A%20blocked%5D) |
| MRs | [3](https://gitlab.com/groups/gitlab-org/-/merge_requests?scope=all&utf8=✓&state=all&label_name[]=workflow%3A%3Ablocked) | [63](https://gitlab.com/groups/gitlab-org/-/merge_requests?scope=all&utf8=%E2%9C%93&state=all&label_name[]=blocked%20%5Bdeprecated%20in%20favor%20of%20workflow%20%3A%20%3A%20blocked%5D) |

Boards were counted by looking at group boards at the gitlab-org level: https://gitlab.com/api/v4/groups/gitlab-org/boards

### Board List
  - [In dev / In review](https://gitlab.com/groups/gitlab-org/-/boards/364214)
  - [Health - Workflow](https://gitlab.com/groups/gitlab-org/-/boards/1160198)
  - [Geo Kanban Build](https://gitlab.com/groups/gitlab-org/-/boards/1181257)
  - [Monitor kick off - Workflow](https://gitlab.com/groups/gitlab-org/-/boards/1223141)
  - [Plan Kanban](https://gitlab.com/groups/gitlab-org/-/boards/1226305)
  - [12.3 Package](https://gitlab.com/groups/gitlab-org/-/boards/1229228)
  - [Team Planning Kanban](https://gitlab.com/groups/gitlab-org/-/boards/1235826)
  - [Certify Kanban](https://gitlab.com/groups/gitlab-org/-/boards/1235846)
  - [Miranda Fluharty](https://gitlab.com/groups/gitlab-org/-/boards/1241526)
  - [Manage::Analytics::Product Process](https://gitlab.com/groups/gitlab-org/-/boards/1244153)


## Action items

* [ ] ~~Triage automation: create or update the stage/group/categories in <https://gitlab.com/gitlab-org/quality/triage-ops/blob/master/lib/devops_labels.rb>.~~
* [ ] ~~(If applicable) Dashboard creation: create or update the stage/group in <https://gitlab.com/gitlab-org/gitlab-insights/blob/master/lib/gitlab_insights.rb>.~~
* [ ] (If applicable) Label migration on existing issues and merge requests: apply the new label to opened & closed issues, and open & merged merge requests. => https://gitlab.com/gitlab-org/quality/triage-ops/merge_requests/238/diffs
* [x] (If applicable) Archive the old label with renaming and adding "DEPRECATED" at the end of the label name.
* [ ] ~~(If applicable) Delete the old dashboard views using the deprecated labels.~~
* [ ] Rename the existing labels based on the following rules
  - [ ] `~workflow::blocked` -> `~workflow::blocked-migrate` - temporary to free up scoped label
  - [ ] `~blocked [deprecated in favor of workflow : : blocked]`  -> `~"workflow::blocked" 
* [ ] Announce that ~"blocked (deprecated) — use workflow : : blocked instead" will be deleted in favor of ~"workflow::blocked"
  * [ ] Company call - Communicated on 8/14
  * [ ] `#development`
  * [ ] `#product`
* [ ]  Delete the ~"blocked [deprecated in favor of workflow : : blocked]" label

/cc @gl-quality/eng-prod

Story points: 2.0