github: update tagging instructions in release checklists

Simplify and standardize the git tag message body. Adding the full
changelog in the tag description feels unnecessary and cannot be
corrected after the fact.

Author: marquiz

.github/ISSUE_TEMPLATE/new-patch-release.md

@@ -18,8 +18,7 @@ Please do not remove items from the checklist
   - [ ] Write the change log into the draft release
   - [ ] Upload release artefacts generated by `prepare-release.sh` script above to the draft release
 - [ ] An OWNER runs
-     `git tag -s $VERSION`
-      and inserts the changelog into the tag description.
+     `git tag -s -m "NFD release $VERSION" $VERSION`
 - [ ] An OWNER pushes the tag with
       `git push $VERSION`
   - Triggers prow to build and publish a staging container image

.github/ISSUE_TEMPLATE/new-release.md

@@ -27,8 +27,7 @@ Please do not remove items from the checklist
   - [ ] Write the change log into the draft release
   - [ ] Upload release artefacts generated by `prepare-release.sh` script above to the draft release
 - [ ] An OWNER runs
-     `git tag -s $VERSION`
-      and inserts the changelog into the tag description.
+     `git tag -s -m "NFD release $VERSION" $VERSION`
 - [ ] An OWNER pushes the tag with
       `git push $VERSION`
   - Triggers prow to build and publish a staging container image