Replace python-versioneer with setuptools-scm

Use setuptools-scm instead of python-versioneer to derive the current
version number from git tags. This is more up-to-date than
python-versioneer and seems to be well established in the Python
ecosystem.

This will fix python-versioneer from creating nondeterministic tarballs
when git-archive or GitHub's archive download feature is used. On the
other hand, those tarballs will no longer contain necessary version
information required for packaging!

If you're creating a custom package of Protontricks using an automated
process, you *WILL* now need to use PyPI tarballs or clone the
repository properly. The PyPI tarball approach is recommended by Arch
Linux's Python package guidelines.

Fixes #44.

.gitignore

@@ -1,5 +1,8 @@
 # Created by https://www.gitignore.io/api/python,virtualenv
 
+# Don't track setuptools-scm generated _version.py
+src/protontricks/_version.py
+
 ### Python ###
 # Byte-compiled / optimized / DLL files
 __pycache__/

MANIFEST.in

@@ -1,3 +1 @@
-include versioneer.py
 include LICENSE
-include src/protontricks/_version.py

requirements_dev.txt

@@ -1,2 +1,3 @@
 pytest>=3.6
 pytest-cov
+setuptools-scm

setup.py

@@ -1,7 +1,5 @@
 from setuptools import setup
 
-import versioneer
-
 
 DESCRIPTION = (
     "A simple wrapper for running Winetricks commands for Proton-enabled "
@@ -18,7 +16,9 @@
 
 setup(
     name="protontricks",
-    version=versioneer.get_version(),
+    use_scm_version={
+        "write_to": "src/protontricks/_version.py"
+    },
     description=DESCRIPTION,
     long_description=LONG_DESCRIPTION,
     author=AUTHOR,
@@ -28,9 +28,8 @@
     packages=["protontricks"],
     package_data={"": ["LICENSE"]},
     package_dir={"protontricks": "src/protontricks"},
-    install_requires=[
-        "vdf>=2.4"
-    ],
+    setup_requires=["setuptools_scm"],
+    install_requires=["vdf>=2.4"],
     entry_points={
         "console_scripts": [
             "protontricks = protontricks.cli:main"
@@ -47,6 +46,4 @@
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7'
     ],
-    cmdclass=versioneer.get_cmdclass()
 )
-

src/protontricks/__init__.py

@@ -3,6 +3,8 @@
 from .gui import *
 from .util import *
 
-from ._version import get_versions
-__version__ = get_versions()['version']
-del get_versions
+try:
+    from ._version import version as __version__
+except ImportError:
+    # Package not installed
+    __version__ = "unknown"