fix: request-ftp requirement (#781)

Author: sbrunato

setup.cfg

@@ -60,7 +60,7 @@ install_requires =
     ecmwf-api-client
     cdsapi
     stream-zip
-    requests_ftp @ https://github.com/Lukasa/requests-ftp/archive/refs/heads/master.zip
+    requests-ftp
 
 [options.extras_require]
 dev =