fix(build): Checkout latest before merging/committing

When conventional-changelog runs v6.24.21, if we're not on the branch that
has the tags, then we're not going to get the right tags, so we need to first checkout the latest
branch which is the one with the tags

ref #455

Author: Kent C. Dodds

scripts/publish-latest.sh

@@ -10,6 +10,10 @@ git config --global user.name formly-bot
 echo "setting remote"
 git remote set-url origin https://formly-bot:$BOT_GH_TOKEN@github.com/formly-js/angular-formly.git >/dev/null 2>/dev/null
 
+echo "checking out latest"
+git fetch
+git checkout latest
+
 echo "merging master"
 git merge origin/master -m "master merge" -X theirs