[eslint-plugin] Silence babel warnings in test

be quiet Babel!

compiler/forget/packages/eslint-plugin-react-forget/babel.config.js

@@ -5,4 +5,11 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-module.exports = { presets: ["@babel/preset-env", "@babel/preset-typescript"] };
+module.exports = {
+  presets: ["@babel/preset-env", "@babel/preset-typescript"],
+  plugins: [
+    ["@babel/plugin-transform-private-property-in-object", { loose: true }],
+    ["@babel/plugin-transform-class-properties", { loose: true }],
+    ["@babel/plugin-transform-private-methods", { loose: true }],
+  ],
+};