Fix link of docs in repo page

[impredicative]

Is there an existing issue for this?

• [X] I have searched the existing issues

Current Behavior

The repo currently links to https://alpaca.markets/docs/python-sdk/ in the About section, but that link is dead.

Expected Behavior

It should instead link to https://alpaca.markets/sdks/python/

Anything else?

See the attached screenshot:

[hiohiohio]

@impredicative thank you very much for the report. I have updated the link to https://docs.alpaca.markets/docs/getting-started-1 The getting started page includes the link to the page you suggested.