chore: fix typo in ruby.md

[Guayaba221]

The typo gprc instead of grpc is important because gRPC is a widely used framework for remote procedure calls (RPC). Any error in its name can cause the code to fail to work properly.

If the wrong name is used, such as gprc, the compiler or interpreter won't recognize it as the correct library, and any functionality relying on gRPC won't work. This will result in compilation or runtime errors, breaking the program.

[guggero]

This is the wrong place to fix the typo. See the PR checklist you removed.