Update pkginfo library to support newer python packages

closes #689

Author: dralley

CHANGES/689.feature

@@ -0,0 +1 @@
+Support Python package metadata version 2.3

pulp_python/app/models.py

@@ -159,6 +159,7 @@ class PythonPackageContent(Content):
     metadata_version = models.TextField()
     summary = models.TextField()
     description = models.TextField()
+    description_content_type = models.TextField()
     keywords = models.TextField()
     home_page = models.TextField()
     download_url = models.TextField()
@@ -171,6 +172,7 @@ class PythonPackageContent(Content):
     project_url = models.TextField()
     platform = models.TextField()
     supported_platform = models.TextField()
+    dynamic = models.TextField()
     requires_dist = models.JSONField(default=list)
     provides_dist = models.JSONField(default=list)
     obsoletes_dist = models.JSONField(default=list)