Make version name compliant with PEP440

pip has deprecated (pypa/pip#8102) version names that do not comply with PEP440 (https://peps.python.org/pep-0440/).
Making this change also avoids what seems to be a bug in newer versions of setuptools which can mangle the shebang (#!) when installing gradient_unwarp.py using the fallback option used by pip for non-compliant packages.

README.md

@@ -46,11 +46,10 @@ First, extract the gradunwarp tarball, and `cd` into the folder it creates. Then
 ```bash
 python3 -m venv gradunwarp.build
 source gradunwarp.build/bin/activate
-pip3 install -r requirements.txt
-pip3 install . --no-cache-dir --no-binary=gradunwarp
+pip install -r requirements.txt
+pip install . 
 deactivate
 ```
-The arguments `--no-cache-dir --no-binary=gradunwarp` are required to suppress a warning arising from the version name of gradunwarp not complying with [python formatting rules](https://peps.python.org/pep-0440/).
 The command `deactivate` ensures that your python environment is set to the way it was before.
 
 After this installation, you can then use gradunwarp by adding

setup.py

@@ -41,7 +41,7 @@ def configuration(parent_package='', top_path=None):
     return config
 
 setup(name='gradunwarp',
-      version = 'HCP-1.2.0',
+      version = '1.2.0+HCP',
       description = 'HCP version of Gradient Unwarping Package for Python/Numpy',
       author = 'Human Connectome Project',
       py_modules  = mods,