Python package installation using pip

[osbm]

I made this small change because it is so much easier to test stuff without cloning repository into your working directory.

You can install forks:

pip install git+https://github.com/osbm/fastMRI_prostate.git

You can install from a branch

pip install git+https://github.com/cai2r/fastMRI_prostate.git@test-branch

You can even install this pull request

pip install git+https://github.com/cai2r/fastMRI_prostate.git@refs/pull/2/merge

just change 2 to the number of this PR