setup.py: Remove custom version handling logic.

This was actually already disabled when updating to newer versioneer
in commit feb4940, but is now further
obsoleted because BuildStream is now dropping the GNOME style version
notation and now follows semver more strictly.

setup.py

@@ -21,8 +21,6 @@
 import re
 import sys
 
-import packaging.version
-
 
 ###################################
 # Ensure we have a version number #
@@ -32,44 +30,6 @@
 sys.path.append(os.path.dirname(__file__))
 import versioneer  # pylint: disable=wrong-import-position
 
-
-def mark_unstable_version(version_string):
-    # When publishing to PyPI we must be sure that unstable releases are
-    # marked as such, so `pip install` doesn't install them by default.
-
-    v = packaging.version.parse(version_string)
-
-    # BuildStream version scheme: if MINOR version is odd, then
-    # this is an unstable release.
-    is_unstable_release = v.minor % 2 != 0
-
-    # Python PEP440 version scheme: use an explicit postfix to mark development
-    # and prereleases.
-    if is_unstable_release:
-        if v.local or v.is_devrelease or v.is_prerelease:
-            # PyPI will ignore these without us marking them.
-            return version_string
-        else:
-            return version_string + ".dev0"
-
-    return version_string
-
-
-# Extend versioneer to support our custom version style.
-_render = versioneer.render
-
-
-def render_version(pieces, style):
-    if style == "pep440_buildstream":
-        result = _render(pieces, "pep440")
-        result["version"] = mark_unstable_version(result["version"])
-    else:
-        result = _render(pieces, style)
-    return result
-
-
-versioneer.render = render_version
-
 version = versioneer.get_version()
 
 if version.startswith("0+untagged"):