Remove metrics tags from train-eval-index

As pointed out by

@lewtun
, the "metrics" tag has been eliminated from "train-eval-index" tag.

README.md

@@ -30,11 +30,6 @@ train-eval-index:
       sentence1: text1
       sentence2: text2
       label: target
-    metrics:
-      - type: accuracy
-        name: Accuracy
-      - type: f1
-        name: F1 binary
   - config: discoverysmall
     task: text-classification
     task_id: multi-class-classification
@@ -45,11 +40,6 @@ train-eval-index:
       sentence1: text1
       sentence2: text2
       label: target
-    metrics:
-      - type: accuracy
-        name: Accuracy
-      - type: f1
-        name: F1 binary
 configs:
 - discovery
 - discoverysmall