chore(root): configure pre-commit hook to format yaml files

including GitHub workflows

Author: ericcrosson-bitgo

.lintstagedrc.json

@@ -1,5 +1,6 @@
 {
   "*.json": ["prettier --write"],
   "*.md": ["prettier --write"],
-  "*.ts": ["prettier --write"]
+  "*.ts": ["prettier --write"],
+  "*.yml": ["prettier --write"]
 }