build!: update library to use Node 12 (#34)

* build!: Update library to use Node 12
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: sofisl

media/livestream/package.json

@@ -4,7 +4,7 @@
   "license": "Apache-2.0",
   "author": "Google LLC",
   "engines": {
-    "node": ">=10"
+    "node": ">=12.0.0"
   },
   "files": [
     "*.js"