uses open library instead of openBrowser function

[tzmanics]

- Summary

For the authorization example in the README.md, switches out the use of the openBrowser function to the open library as suggested by @ehmicky. This makes the example a little more encapsulated.

- A picture of a cute animal (not mandatory but encouraged)

[tzmanics]

Hi @erezrokah thanks for the 👍, on further review, I saw another fix in changing api to client to match the other example code in the readme. Sorry for the change, hope it's ok!

[erezrokah]

Hi @erezrokah thanks for the 👍, on further review, I saw another fix in changing api to client to match the other example code in the readme. Sorry for the change, hope it's ok!

This is great, thank you for following up with that fix :)

[erezrokah]

@tzmanics I changed the required checks per #271
Let me know when you're ready and I can merge this one (or you can wait for #271 and rebase).

Update

We're postponing #271

[tzmanics]

I think it's good to merge this one now and I can re-check after #271 is merged. THanks!