Correctly Print Task Versioning (#1173)

* change version field formatting in metadata

* mention versioning in new task guide

* add instructions for changelog

* run linters

lm_eval/tasks/wikitext/wikitext.yaml

@@ -15,4 +15,4 @@ metric_list:
   - metric: byte_perplexity
   - metric: bits_per_byte
 metadata:
-  - version: 2.0
+  version: 2.0

lm_eval/tasks/winogrande/default.yaml

@@ -14,4 +14,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  - version: 1.0
+  version: 1.0

lm_eval/tasks/wmt2016/ro_en-t5_prompt.yaml

@@ -16,4 +16,4 @@ metric_list:
     aggregation: !function metrics.agg_bleu
     higher_is_better: true
 metadata:
-  - version: 0.0
+  version: 0.0

lm_eval/tasks/wsc273/default.yaml

@@ -14,4 +14,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  - version: 1.0
+  version: 1.0

lm_eval/tasks/xcopa/default_et.yaml

@@ -11,4 +11,4 @@ doc_to_choice: !function utils.doc_to_choice
 metric_list:
   - metric: acc
 metadata:
-  - version: 1.0
+  version: 1.0

lm_eval/tasks/xnli/xnli_common_yaml

@@ -16,4 +16,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  - version: 1.0
+  version: 1.0

lm_eval/tasks/xstorycloze/default_ar.yaml

@@ -15,4 +15,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  - version: 1.0
+  version: 1.0

lm_eval/tasks/xwinograd/xwinograd_common_yaml

@@ -17,4 +17,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  - version: 1.0
+  version: 1.0