fix: Use PEP440 compliant version in setup.py

Versions like `0.176ubuntu20.04.1` in Ubuntu are clearly not compliant
with https://peps.python.org/pep-0440/. With setuptools 66, the versions
of all packages visible in the Python environment *must* obey PEP440.

Bug: https://launchpad.net/bugs/1991606
Signed-off-by: Benjamin Drung <benjamin.drung@canonical.com>

setup.py

@@ -5,6 +5,19 @@ import glob
 import os
 import re
 
+
+def make_pep440_compliant(version: str) -> str:
+    """Convert the version into a PEP440 compliant version."""
+    public_version_re = re.compile(r"^([0-9][0-9.]*(?:(?:a|b|rc|.post|.dev)[0-9]+)*)\+?")
+    _, public, local = public_version_re.split(version, maxsplit=1)
+    if not local:
+        return version
+    sanitized_local = re.sub("[+~]+", ".", local).strip(".")
+    pep440_version = f"{public}+{sanitized_local}"
+    assert re.match("^[a-zA-Z0-9.]+$", sanitized_local), f"'{pep440_version}' not PEP440 compliant"
+    return pep440_version
+
+
 # look/set what version we have
 changelog = "debian/changelog"
 if os.path.exists(changelog):
@@ -67,7 +80,7 @@ data_files = [
 if __name__ == '__main__':
     setup(
         name='ubuntu-dev-tools',
-        version=version,
+        version=make_pep440_compliant(version),
         scripts=scripts,
         packages=[
             'ubuntutools',