Merge pull request #5075 from ralfhandl/main-contributing-branch-role-of-vX.Y.Z-rel

main: changed role of `vX.Y.Z-rel` branches

Author: miqui

CONTRIBUTING.md

@@ -373,7 +373,7 @@ For information on the branch and release strategy for OAS 3.0.4 and 3.1.1 and e
 * `dev` is the primary branch for working with the `src` tree. Development infrastructure that is not needed on `main` is maintained here, and can be merged out to other non-`main` branches as needed.
  Changes on `main` are automatically included in a pull request to `dev` (see the (section on [branch sync](#branch-sync-automation)).
 * `vX.Y-dev` is the minor release line development branch for X.Y, including both the initial X.Y.0 minor version and all subsequent X.Y.Z patch versions. All PRs are made to oldest active `vX.Y-dev` branch to which the change is relevant, and then merged forward as shown in the diagram further down in this document.
-* `vX.Y.Z-rel` is the release branch for an X.Y.Z release (including when Z == 0). It exists primarily for `git mv`-ing `src/oas.md` to the appropriate `versions/X.Y.Z.md` location and removing schema-related files before merging back to `main`, and can also be used for any emergency post-release fixes that come up, such as when a 3rd party changes URLs in a way that breaks published links.
+* `vX.Y.Z-rel` is the release branch for an X.Y.Z release (including when Z == 0). It exists primarily for `git mv`-ing `src/oas.md` to the appropriate `versions/X.Y.Z.md` location and removing schema-related files before merging back to `main`, and is deleted once merged into `main` via a pull request.
 
 ### Branching and merging (3.1.2, 3.2.0, and later)