BLD: use pyproject.toml not setup.py

While at it, remove versioneer and use setuptools_scm
for computing the version dynamically.
This change is mainly because I did not manage to make
versioneer work with pyproject.toml, while setuptools_scm
"just worked" (well, nearly).

Author: ev-br

.gitignore

@@ -26,6 +26,9 @@ share/python-wheels/
 *.egg
 MANIFEST
 
+*_version.py
+
+
 # PyInstaller
 #  Usually these files are written by a python script from a template
 #  before PyInstaller builds the exe, so as to inject date/other infos into it.

array_api_strict/__init__.py

@@ -327,9 +327,12 @@
 
 __all__ += ['set_array_api_strict_flags', 'get_array_api_strict_flags', 'reset_array_api_strict_flags', 'ArrayAPIStrictFlags']
 
-from . import _version
-__version__ = _version.get_versions()['version']
-del _version
+try:
+    from . import _version
+    __version__ = _version.__version__
+    del _version
+except ImportError:
+    __version__ = "unknown"
 
 
 # Extensions can be enabled or disabled dynamically. In order to make