Add Typescript SDK CI

[tillrohrmann]

In order to catch bugs early on in the development cycle, I'd suggest to add CI to the typescript SDK repository.

### Tasks
- [ ] #72
- [ ] https://github.com/restatedev/sdk-typescript/issues/75

[tillrohrmann]

@jackkleeman do you wanna take care of this issue?

[tillrohrmann]

Thanks for addressing this issue @jackkleeman. Closing it as done.