Add "release" as an alias for the empty/release qualifier.

The Maven ComparableVersion spec defines "", "final", "ga", and "release"
as equivalent, but univers is missing "release".

Fixes #188

Author: selsky

src/univers/maven.py

@@ -33,6 +33,7 @@ class RestrictionParseError(ValueError):
 ALIASES = {
     "ga": "",
     "final": "",
+    "release": "",
     "cr": "rc",
 }