fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-INFLIGHT-6095116

Author: snyk-bot

package.json

@@ -28,7 +28,7 @@
     "graphql-relay": "^0.6.0",
     "graphql-resolve-batch": "^1.0.2",
     "graphql-subscriptions": "^1.0.0",
-    "grpc": "^1.24.3",
+    "grpc": "^1.24.8",
     "js-xdr": "^1.1.0",
     "minimist": "^1.2.3",
     "object-dig": "^0.1.3",