Bump google.golang.org/protobuf in /examples/grpc-demo

Bumps google.golang.org/protobuf from 1.31.0 to 1.33.0.

---
updated-dependencies:
- dependency-name: google.golang.org/protobuf
  dependency-type: direct:production
...

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

examples/grpc-demo/go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/yoyofx/yoyogo v0.0.0
 	github.com/yoyofxteam/dependencyinjection v1.0.1
 	google.golang.org/grpc v1.60.0
-	google.golang.org/protobuf v1.31.0
+	google.golang.org/protobuf v1.33.0
 )
 
 require (