Don't use unauthenticated git port

[danjohnson95]

I'm getting this error when running setup-dump1090.sh

0 upgraded, 0 newly installed, 0 to remove and 302 not upgraded.
Cloning into 'dump1090'...
fatal: remote error:
The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
./setup-dump1090.sh: line 5: cd: dump1090: No such file or directory
make: *** No targets specified and no makefile found. Stop.

This is because it's using the git:// protocol to clone the repo, which is no longer supported when unauthenticated.