Drop setuptools_scm runtime use.

Author: anntzer

Diff for: lib/mplcairo/__init__.py

@@ -1,15 +1,9 @@
 import sys
 
 try:
-    import setuptools_scm
-    __version__ = setuptools_scm.get_version(  # xref setup.py
-        root="../..", relative_to=__file__,
-        version_scheme="post-release", local_scheme="node-and-date")
-except (ImportError, LookupError):
-    try:
-        from ._version import version as __version__
-    except ImportError:
-        pass
+    from ._version import version as __version__
+except ImportError:
+    __version__ = "(unknown version)"
 
 if sys.platform != "win32":
     def _load_symbols():