Don't use fixed version

Author: schmidt-sebastian

packages/firestore/package.json

@@ -71,7 +71,7 @@
     "@firebase/logger": "0.2.6",
     "@firebase/util": "1.1.0",
     "@firebase/webchannel-wrapper": "0.4.1",
-    "@grpc/grpc-js": "1.3.0",
+    "@grpc/grpc-js": "^1.3.0",
     "@grpc/proto-loader": "^0.5.0",
     "node-fetch": "2.6.1",
     "tslib": "^2.1.0"