Update dependency grpc to v1.20.3

Author: renovate-bot

package-lock.json

@@ -56,7 +56,7 @@
     "fastify-formbody": "3.1.0",
     "fastify-multipart": "0.8.1",
     "graphql": "14.3.0",
-    "grpc": "1.20.0",
+    "grpc": "1.20.3",
     "http2": "3.3.7",
     "iterare": "1.1.2",
     "merge-graphql-schemas": "1.5.8",

package.json

@@ -17,7 +17,7 @@
     "@nestjs/testing": "6.1.1",
     "class-transformer": "0.2.2",
     "class-validator": "0.9.1",
-    "grpc": "1.20.0",
+    "grpc": "1.20.3",
     "reflect-metadata": "0.1.13",
     "rxjs": "6.5.1",
     "typescript": "3.4.5"