maven.py: "release" qualifier not treated as release alias

What: `ALIASES` dict in `maven.py` maps `"ga"` and `"final"` to `""` but omits `"release"`. So `Version("1.0") ==
Version("1.0-release")` returns `False`.

Expected: The Maven `ComparableVersion` spec defines `""`, `"final"`, `"ga"`, and `"release"` as equivalent.
Reference: https://maven.apache.org/pom.html#version-order-specification

Fix: Add `"release": ""` to the `ALIASES` dict on line 33 of `univers/maven.py`.

Reproduction:
```from univers.maven import Version
assert Version("1.0") == Version("1.0-release") # fails
assert Version("1.0") == Version("1.0-final") # passes
assert Version("1.0") == Version("1.0-ga") # passes
```