chore: fix sdiff version to 0.4.1 because 1.0.0 will be incompatible with python 3.6 (#36)

Author: b1r3k

setup.py

@@ -10,7 +10,7 @@ def read(f):
 
 
 install_requires = [
-    'sdiff @ git+https://github.com/KeepSafe/html-structure-diff.git#egg=sdiff',
+    'sdiff @ git+https://github.com/KeepSafe/html-structure-diff.git@0.4.1#egg=sdiff',
     'aiohttp >=3, <3.4',
     'Markdown',
     'parse >=1, <2',