add link to epidatpy api keys handling

Author: nmdefries

docs/api/api_keys.md

@@ -42,11 +42,12 @@ there are several ways to use your key to authenticate your requests:
 
 ### Using a client
 
-* covidcast
+* [epidatr](https://cmu-delphi.github.io/epidatr/#api-keys)
+* [epidatpy](https://github.com/cmu-delphi/epidatpy/blob/dev/docs/index.rst#api-keys)
+* [delphi-epidata](https://cmu-delphi.github.io/delphi-epidata/api/client_libraries.html)
+* covidcast (deprecated in favor of `epidatr` and `epidatpy`)
   * [R client](https://cmu-delphi.github.io/covidcast/covidcastR/reference/covidcast_signal.html#api-keys-1)
   * [Python client](https://cmu-delphi.github.io/covidcast/covidcast-py/html/signals.html#covidcast.use_api_key)
-* [epidatr](https://github.com/cmu-delphi/epidatr#api-keys)
-* [delphi-epidata](https://cmu-delphi.github.io/delphi-epidata/api/client_libraries.html)
 
 ### Via request parameter