Use importlib for versioning

The semver parsing in PBR doesn't handle the full suite of pep440
versions (for example: 1.2.3+foo1 is the pep440 recommended way
of handling local versions).

Since we aren't doing anything with the parsed versions anyway,
just return the string we get from importlib.

Change-Id: I0a838c639333c40db5b12cd852b921f1b1c87fed

zuul/cmd/__init__.py

@@ -105,8 +105,8 @@ class ZuulApp(object):
         self.commands = {}
 
     def _get_version(self):
-        from zuul.version import version_info as zuul_version_info
-        return "Zuul version: %s" % zuul_version_info.release_string()
+        from zuul.version import release_string
+        return "Zuul version: %s" % release_string
 
     def createParser(self):
         parser = argparse.ArgumentParser(
@@ -226,12 +226,12 @@ class ZuulDaemonApp(ZuulApp, metaclass=abc.ABCMeta):
 
     def setup_logging(self, section, parameter):
         super(ZuulDaemonApp, self).setup_logging(section, parameter)
-        from zuul.version import version_info as zuul_version_info
+        from zuul.version import release_string
         log = logging.getLogger(
             "zuul.{section}".format(section=section.title()))
         log.debug(
             "Configured logging: {version}".format(
-                version=zuul_version_info.release_string()))
+                version=release_string))
 
     def main(self):
         self.parseArguments()

zuul/version.py

@@ -17,11 +17,10 @@
 
 import json
 
-import pbr.version
+from importlib import metadata as importlib_metadata
 import pkg_resources
 
-version_info = pbr.version.VersionInfo('zuul')
-release_string = version_info.release_string()
+release_string = importlib_metadata.distribution('zuul').version
 
 is_release = None
 git_version = None