Mark msal 0.5.x as compatible with the extension. (#28)

Author: marstr

setup.py

@@ -16,7 +16,7 @@
         'Development Status :: 2 - Pre-Alpha',
     ],
     install_requires=[
-        'msal~=0.4.1',
+        'msal>=0.4.1,<0.6.0',
         'portalocker~=1.0',
     ],
     tests_require=['pytest'],