Remove usage of release branch

The release process can function fine without a release branch, and he version tags should be sufficient for anyone looking for the latest release in git history.

If anything, we can replace the release branch with a git tag which is updated by the release script, but I don't see any immediate need for one.

.github/workflows/release.yaml

@@ -28,7 +28,7 @@ jobs:
         with:
           name: dist
           path: dist/
-      - run: git push origin master release tag ${{ github.event.inputs.version}}
+      - run: git push origin master tag ${{ github.event.inputs.version}}
       - name: 'Publish to PyPI'
         run: twine upload dist/*
         env:

devel/release

@@ -35,7 +35,6 @@ main() {
     update-version $version
     update-changelog $version
     commit-and-tag $version
-    merge-to-release-branch $version
     build-dist
     remind-to-push $version
 }
@@ -149,15 +148,6 @@ commit-and-tag() {
     fi
 }
 
-merge-to-release-branch() {
-    local version="$1"
-
-    git checkout release
-    git pull --ff-only
-    git merge --ff-only "$version"
-    git checkout -
-}
-
 build-dist() {
     rm -rfv build/ dist/ nextstrain_augur.egg-info
     python3 -m build
@@ -172,7 +162,7 @@ remind-to-push() {
     echo
     echo "Please remember to push, including tags:"
     echo
-    echo "   git push origin master release tag $version"
+    echo "   git push origin master tag $version"
     echo
     echo "You'll also want to upload the built releases to PyPi:"
     echo