Update README.md

[ugoi]

No description provided.

[jeer00]

I couldnt figure out if i where to open an issue or reply here, but since this PR is about the ts-example:

The types dont seem to work when using require? And when instead using an es6 import, the types work, but then it just returns typeerror:

TypeError: Cannot read properties of undefined (reading 'TransactionalEmailsApi')
This was solved by awaiting the import:
const brevo = await import('@getbrevo/brevo');

So, would it be reasonable to update the readme with es6 imports?