Update release checklist for new archived docs strategy

Author: sadielbartholomew

RELEASE.md

@@ -132,7 +132,9 @@
     5. Remove duplicate words and sort alphabetically via:
        `sort -u -o docs/source/spelling_false_positives.txt docs/source/spelling_false_positives.txt`
 
-- [ ] Create an archived copy of the documentation:
+- [ ] For major or epoch releases *only* (i.e. not minor, see the versioning strategy at
+  https://ncas-cms.github.io/cf-python/releases.html#versioning-strategy)
+  create an archived copy of the documentation:
 
   ```bash
   ./release_docs archive
@@ -181,9 +183,9 @@
 
 - [ ] Upload the new release to Zenodo: https://zenodo.org/record/3961353
 
-- [ ] Copy the archive docs to https://github.com/NCAS-CMS/cf-python-docs
-
-- [ ] Move and commit the previously-generated archived copy of the documentation to https://github.com/NCAS-CMS/cf-python-docs (fork or clone that repo first):
+- [ ] For major or epoch releases *only*, move the archive docs generated earlier to
+  https://github.com/NCAS-CMS/cf-python-docs and commit them (you may have to
+  fork or clone that repo first):
 
   ```bash
   mv docs/<vn>/ ~/cf-python-docs/