Replace git protocol URL in docs with an HTTPS URL

Author: oliviacrain

docs/user/install.rst

@@ -22,7 +22,7 @@ Requests is actively developed on GitHub, where the code is
 
 You can either clone the public repository::
 
- $ git clone git://github.com/psf/requests.git
+ $ git clone https://github.com/psf/requests.git
 
 Or, download the `tarball <https://github.com/psf/requests/tarball/main>`_::