chore(deps): unpin grpc (#475)

Author: alexander-fenster

packages/packages/google-gax/package.json

@@ -13,7 +13,7 @@
     "@grpc/proto-loader": "^0.5.0",
     "duplexify": "^3.6.0",
     "google-auth-library": "^3.0.0",
-    "grpc": "1.20.0",
+    "grpc": "^1.20.2",
     "grpc-gcp": "^0.1.1",
     "is-stream-ended": "^0.1.4",
     "lodash.at": "^4.6.0",

packages/packages/google-gax/system-test/fixtures/google-gax-packaging-test-app/package.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "@grpc/grpc-js": "^0.3.6",
     "google-gax": "file:./google-gax.tgz",
-    "grpc": "1.20.0",
+    "grpc": "^1.20.2",
     "lodash.merge": "^4.6.1",
     "protobufjs": "^6.8.8"
   },