Updates security release issue template

Related to https://gitlab.com/groups/gitlab-com/gl-infra/-/epics/121

.gitlab/issue_templates/Security developer workflow.md

 <!--
 # Read me first!
 
-Create this issue under https://dev.gitlab.org/gitlab/gitlabhq
+Create this issue under https://gitlab.com/gitlab-org/security
 
 Set the title to: `Description of the original issue`
 -->
 
-### Prior to starting the security release work
+## Prior to starting the security release work
 
 - [ ] Read the [security process for developers] if you are not familiar with it.
-- [ ] Link to the original issue adding it to the [links section](#links)
-- [ ] Run `scripts/security-harness` in the CE, EE, and/or Omnibus to prevent pushing to any remote besides `dev.gitlab.org`
-- [ ] Create a new branch prefixing it with `security-`
-- [ ] Create a MR targeting `dev.gitlab.org` `master`
-- [ ] Add a link to this issue in the original security issue on `gitlab.com`.
+- [ ] Link this issue in the Security Release issue on GitLab.com. You can find this issue in the topic of the `#releases` channel.
+- [ ] Add a link to the confidential `gitlab-org/gitlab` issue describing the vulnerability next to **Original issue** in the [links table](#links).
+- [ ] Add a link to the confidential `gitlab-org/gitlab` Security release issue next to **Security release issue** in the [links table](#links).
+- [ ] Run `scripts/security-harness` in your local repository to prevent accidentally pushing to any remote besides `gitlab.com/gitlab-org/security`.
 
-#### Backports
+## Development
 
-- [ ] Once the MR is ready to be merged, create MRs targeting the latest 3 stable branches
-    - [ ] At this point, it might be easy to squash the commits from the MR into one
-    - You can use the script `bin/secpick` instead of the following steps, to help you cherry-picking. See the [secpick documentation]
-    - [ ] Create each MR targeting the stable branch `X-Y-stable`, using the "Security Release" merge request template.
-    - Every merge request will have its own set of TODOs, so make sure to
-      complete those.
-- [ ] Make sure all MRs have a link in the [links section](#links)
+- [ ] Create a new branch prefixing it with `security-`.
+- [ ] Create a merge request targeting `master` on `gitlab.com/gitlab-org/security` and use the [Security Release merge request template].
+- [ ] Follow the same [code review process]: Assign to a reviewer, then to a maintainer.
 
-[secpick documentation]: https://gitlab.com/gitlab-org/release/docs/blob/master/general/security/developer.md#secpick-script
+After your merge request has being approved according to our [approval guidelines], you're ready to prepare the backports
+
+## Backports
 
-#### Documentation and final details
+- [ ] Once the MR is ready to be merged, create MRs targeting the latest 3 stable branches
+   * At this point, it might be easy to squash the commits from the MR into one
+   * You can use the script `bin/secpick` instead of the following steps, to help you cherry-picking. See the [secpick documentation]
+- [ ] Create each MR targeting the stable branch `X-Y-stable`, using the [Security Release merge request template].
+   * Every merge request will have its own set of TODOs, so make sure to complete those.
+- [ ] Make sure all MRs are linked in the [Links section](#links)
+
+## Documentation and final details
 
-- [ ] Check the topic on #releases to see when the next release is going to happen and add a link to the [links section](#links)
-- [ ] Add links to this issue and your MRs in the description of the security release issue
+- [ ] Ensure the [Links section](#links) is completed.
 - [ ] Find out the versions affected (the Git history of the files affected may help you with this) and add them to the [details section](#details)
 - [ ] Fill in any upgrade notes that users may need to take into account in the [details section](#details)
 - [ ] Add Yes/No and further details if needed to the migration and settings columns in the [details section](#details)
 - [ ] Add the nickname of the external user who found the issue (and/or HackerOne profile) to the Thanks row in the [details section](#details)
 - [ ] Once your `master` MR is merged, comment on the original security issue with a link to that MR indicating the issue is fixed.
 
-### Summary
+## Summary
 
-#### Links
+### Links
 
 | Description | Link |
 | -------- | -------- |
 | Original issue   | #TODO  |
 | Security release issue   | #TODO  |
 | `master` MR | !TODO   |
-| `master` MR (EE) | !TODO   |
 | `Backport X.Y` MR | !TODO   |
 | `Backport X.Y` MR | !TODO   |
 | `Backport X.Y` MR | !TODO   |
-| `Backport X.Y` MR (EE) | !TODO   |
-| `Backport X.Y` MR (EE) | !TODO   |
-| `Backport X.Y` MR (EE) | !TODO   |
 
-#### Details
+### Details
 
 | Description | Details | Further details|
 | -------- | -------- | -------- |
@@ -65,6 +64,9 @@ Set the title to: `Description of the original issue`
 | Thanks | | |
 
 [security process for developers]: https://gitlab.com/gitlab-org/release/docs/blob/master/general/security/developer.md
-[RM list]:  https://about.gitlab.com/release-managers/
+[secpick documentation]: https://gitlab.com/gitlab-org/release/docs/blob/master/general/security/developer.md#secpick-script
+[security Release merge request template]: https://gitlab.com/gitlab-org/security/gitlab/blob/master/.gitlab/merge_request_templates/Security%20Release.md
+[code review process]: https://docs.gitlab.com/ee/development/code_review.html
+[approval guidelines]: https://docs.gitlab.com/ee/development/code_review.html#approval-guidelines
 
 /label ~security