Revert "fix: Add return type hint to Metric.read() (#110)" (#173)

This reverts commit f23a4ea.

fgpyo/util/metric.py

@@ -158,7 +158,7 @@ def _parsers(cls) -> Dict[type, Callable[[str], Any]]:
         return {}
 
     @classmethod
-    def read(cls, path: Path, ignore_extra_fields: bool = True) -> Iterator["Metric[MetricType]"]:
+    def read(cls, path: Path, ignore_extra_fields: bool = True) -> Iterator[Any]:
         """Reads in zero or more metrics from the given path.
 
         The metric file must contain a matching header.