feat: Support list in value matches mapping_spec

This changes makes the mapping specification, allowing the "matches"
in the spec contain lists (in addition to tuples, which were already
supported). Example:

    mappings = [
        {
            "source": "src_column",
            "target": "tgt_column",
            "matches": [
                ["Red Apple", "APPLE"],
                ["Banana", "BANANA"],
                ["Oorange", "ORANGE"],
            ],
        }
    ]

bdikit/api.py

@@ -836,15 +836,15 @@ def _create_mapper_from_value_matches(matches: List[ValueMatch]) -> DictionaryMa
     for match in matches:
         if isinstance(match, ValueMatch):
             mapping_dict[match.source_value] = match.target_value
-        elif isinstance(match, tuple) and len(match) == 2:
+        elif (isinstance(match, tuple) or isinstance(match, list)) and len(match) == 2:
             if isinstance(match[0], str) and isinstance(match[1], str):
                 mapping_dict[match[0]] = match[1]
             else:
                 raise ValueError(
                     "Tuple in matches must contain two strings: (source_value, target_value)"
                 )
         else:
-            raise ValueError("Matches must be a list of ValueMatch objects or tuples")
+            raise ValueError("Matches must be a list of ValueMatch objects or tuples with two values.")
     return DictionaryMapper(mapping_dict)