Fix typo in error message for runtime validation

Author: ytetsuro

src/deploy/functions/runtimes/node/parseRuntimeAndValidateSDK.ts

@@ -15,7 +15,7 @@ const supportedNodeVersions: string[] = Object.keys(supported.RUNTIMES)
 export const RUNTIME_NOT_SET =
   "`runtime` field is required but was not found in firebase.json or package.json.\n" +
   "To fix this, add the following lines to the `functions` section of your firebase.json:\n" +
-  `"runtime": "${supported.latest("nodejs")}" or set the "engine" field in package.json\n`;
+  `"runtime": "${supported.latest("nodejs")}" or set the "engines" field in package.json\n`;
 
 function getRuntimeChoiceFromPackageJson(sourceDir: string): supported.Runtime {
   const packageJsonPath = path.join(sourceDir, "package.json");