build(deps): bump graphql from 15.3.0 to 15.4.0

Bumps [graphql](https://github.com/graphql/graphql-js) from 15.3.0 to 15.4.0.
- [Release notes](https://github.com/graphql/graphql-js/releases)
- [Commits](https://github.com/graphql/graphql-js/compare/v15.3.0...v15.4.0)

Signed-off-by: dependabot[bot] <support@github.com>

plugins/graphiql/package.json

@@ -37,7 +37,7 @@
     "@material-ui/icons": "^4.9.1",
     "@material-ui/lab": "4.0.0-alpha.45",
     "graphiql": "^1.0.0-alpha.10",
-    "graphql": "15.3.0",
+    "graphql": "15.4.0",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
     "react-use": "^15.3.3"