Update cot_yaml

lm_eval/tasks/mgsm/native_cot/cot_yaml

@@ -14,10 +14,15 @@ generation_kwargs:
     - "\n"
   do_sample: false
   temperature: 0.0
-target_delimiter: " "
 metric_list:
   - metric: exact_match
     aggregation: mean
     higher_is_better: true
     ignore_case: true
     ignore_punctuation: true
+filter_list:
+  - name: "get-answer"
+    filter:
+      - function: "regex"
+        regex_pattern: "The answer is (\\-?[0-9\\.\\,]+)"
+      - function: "take_first"