use setuptools_scm for python version management (#627)

* use setuptools_scm for python version management

* add git dep for python wheel building

* if no tag is defined, default to dev

* any untagged version default to 0.0.1

crates/misc/py/setup.py

@@ -1,8 +1,14 @@
 from setuptools import setup
 from setuptools_rust import Binding, RustExtension
 
+
+def no_tag_default_to_dev(version):
+    if version.exact:
+        return version.format_with("{tag}")
+    return "0.0.1"
+
+
 setup(name='wasmtime',
-      version="0.0.1",
       classifiers=[
             "Development Status :: 1 - Planning",
             "Intended Audience :: Developers",
@@ -14,5 +20,12 @@ setup(name='wasmtime',
       ],
       packages=['wasmtime'],
       package_dir={'wasmtime': 'python/wasmtime'},
+      use_scm_version = {
+          "root": "../../..",
+          "relative_to": __file__,
+          "version_scheme": no_tag_default_to_dev,
+          "local_scheme": lambda _: "",
+      },
+      setup_requires=['setuptools_scm'],
       rust_extensions=[RustExtension('wasmtime.lib_wasmtime', 'Cargo.toml',  binding=Binding.PyO3)],
       zip_safe=False)