chore(deps): bump @grpc/grpc-js from 1.9.7 to 1.9.15 in /zeebe-extra

Bumps [@grpc/grpc-js](https://github.com/grpc/grpc-node) from 1.9.7 to 1.9.15.
- [Release notes](https://github.com/grpc/grpc-node/releases)
- [Commits](https://github.com/grpc/grpc-node/compare/@grpc/[email protected]...@grpc/[email protected])

---
updated-dependencies:
- dependency-name: "@grpc/grpc-js"
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

zeebe-extra/package.json

@@ -66,7 +66,7 @@
 		]
 	},
 	"dependencies": {
-		"@grpc/grpc-js": "1.9.7",
+		"@grpc/grpc-js": "1.9.15",
 		"@grpc/proto-loader": "0.7.10",
 		"chalk": "^2.4.2",
 		"console-stamp": "^3.0.2",