Fix version import (#81)

* Update __init__.py

update version file import

* Update test_ufonormalizer.py

Check that package version is not the fallback value of "unknown".

src/ufonormalizer/__init__.py

@@ -16,7 +16,7 @@
 import logging
 
 try:
-    from _version import __version__
+    from ._version import __version__
 except ImportError:
     try:
         from setuptools_scm import get_version

tests/test_ufonormalizer.py

@@ -1582,6 +1582,11 @@ def test_normalizeLibPlistWithBytesData(self):
                 Ny8wOS8yNiAwOToxMzoyMXEGc31xB2JzLg==
                 """))
 
+    def test_version_not_unknown(self):
+        """Test that package version is not 'unknown', which should only happen in cases
+        where the package has not been installed and is outside of source control. """
+        self.assertNotEqual(ufonormalizerVersion, 'unknown')
+
 
 class XMLWriterTest(unittest.TestCase):
     def __init__(self, methodName):