Remove encoding keyword from json()

* Removed in Python 3.9

Signed-off-by: Alfred Wingate <parona@protonmail.com>

src/euscan/handlers/gnome.py

@@ -55,7 +55,7 @@ def scan_pkg(pkg, options):
     content = fp.read()
     fp.close()
 
-    cache = json.loads(content, encoding="ascii")
+    cache = json.loads(content)
 
     if cache[0] != 4:
         output.eerror("Unknow cache format detected")