Make sure still support Python >= 3.5.3

gns3server/run.py

@@ -236,7 +236,7 @@ def run():
             return
         log.info("HTTP authentication is enabled with username '{}'".format(user))
 
-    # we only support Python 3 version >= 3.5
+    # we only support Python 3 version >= 3.5.3
     if sys.version_info < (3, 5, 3):
         raise SystemExit("Python 3.5.3 or higher is required")
 

requirements.txt

@@ -1,3 +1,4 @@
+yarl==1.3.0  # yarl 1.4+ requires Python 3.6+ (needed by aiohttp and aiohttp-cors)
 jsonschema==2.6.0  # pyup: ignore
 aiohttp==3.6.2
 aiohttp-cors==0.7.0