Update start-prerelease script

Author: brophdawg11

scripts/start-prerelease.sh

@@ -14,6 +14,12 @@ git checkout dev
 git pull
 git checkout -b release-next
 git merge main --no-edit
+
+if [[ -n $(git status --porcelain) ]]; then
+  echo "Error: Your git working directory is not clean after merging main ito release-next."
+  exit 1
+fi
+
 pnpm changeset pre enter pre
 git add .changeset/pre.json
 git commit -m "Enter prerelease mode"