use new package.json exports

Author: AbhiPrasad

packages/google-cloud/package.json

@@ -18,6 +18,19 @@
   "main": "build/cjs/index.js",
   "module": "build/esm/index.js",
   "types": "build/types/index.d.ts",
+  "exports": {
+    "./package.json": "./package.json",
+    ".": {
+      "import": {
+        "types": "./build/types/index.d.ts",
+        "default": "./build/esm/index.js"
+      },
+      "require": {
+        "types": "./build/types/index.d.ts",
+        "default": "./build/cjs/index.js"
+      }
+    }
+  },
   "typesVersions": {
     "<4.9": {
       "build/types/index.d.ts": [