Git clone URL protocol moved from git:// to https:// protocol

[MichelBoucey]

During the Cabal (v3.16.0.0) build process (with GHC 9.12.2) the message below is emitted:

Warning: [git-protocol] Cloning over git:// might lead to an arbitrary code
execution vulnerability. Furthermore, popular forges like GitHub do not
support it. Use https:// or ssh:// instead.

In the PR, I just changed the Git clone URL protocol from git:// to https:// protocol in aeson.cabal file and in README.markdown file accordingly. After this change, the message is no more present for the package aeson.

B.T.W. : the message is emitted per package.