properly parse release tags

rainboard/models.py

@@ -369,9 +369,15 @@ class Project(Links, NamedModel, TimeStampedModel):
         self.update_repo()
         tags = self.tag_set.filter(name__startswith='v')  # TODO: implement SQL ordering for semver
         if tags.exists():
-            self.version = '%i.%i.%i' % sorted(
-                tuple(int(v) for v in t.name[1:].split('.'))
-                for t in tags if not any(v in t.name for v in ['-', 'rc']))[-1]
+            releases = []
+            for tag in tags:
+                try:
+                    release = tuple(int(v) for v in tag.name[1:].split('.'))
+                    releases.append(release)
+                except ValueError:
+                    pass
+            if releases:
+                self.version = '%i.%i.%i' % sorted(releases)[-1]
         robotpkg = self.robotpkg_set.order_by('-updated').first()
         branch = self.branch_set.order_by('-updated').first()
         branch_updated = branch is not None and branch.updated is not None