Add simple tests to validate that we're able to get the version

Add a test to ensure that for every version of Python we support we're
able to get the version. Not checking what that version is as that
almost defeats the point of the test.

tests/test_init.py

@@ -0,0 +1,8 @@
+import jazzmin
+
+
+def test_version():
+    """
+    Tests getting the version of the installed package in all versions of Python we support.
+    """
+    assert jazzmin.version >= "0.0.0"