Fix config parser to properly allow equals in all arguments

This commit fixes the config file parser to allow an optional equals
sign as an argument separator for all arguments. The previous code
allowed this for the first argument on a line, but not later ones.

asyncssh/config.py

@@ -315,22 +315,26 @@ def parse(self, path: Path) -> None:
                     continue
 
                 try:
-                    args = shlex.split(line)
+                    split_args = shlex.split(line)
                 except ValueError as exc:
                     self._error(str(exc))
 
-                option = args.pop(0)
-
-                if option.endswith('='):
-                    option = option[:-1]
-                elif '=' in option:
-                    option, arg = option.split('=', 1)
-                    args[:0] =[arg]
-                elif args and args[0] == '=':
-                    del args[0]
-                elif args and args[0].startswith('='):
-                    args[0] = args[0][1:]
+                args = []
+
+                for arg in split_args:
+                    if arg.startswith('='):
+                        if len(arg) > 1:
+                            args.append(arg[1:])
+                    elif arg.endswith('='):
+                        args.append(arg[:-1])
+                    elif '=' in arg:
+                        arg, val = arg.split('=', 1)
+                        args.append(arg)
+                        args.append(val)
+                    else:
+                        args.append(arg)
 
+                option = args.pop(0)
                 loption = option.lower()
 
                 if loption in self._no_split: