added subgroups for other mmlu variants

lm_eval/tasks/mmlu/flan_cot_zeroshot/_mmlu.yaml

+group: mmlu_flan_cot_zeroshot
+task:
+  - mmlu_flan_cot_zeroshot_stem
+  - mmlu_flan_cot_zeroshot_other
+  - mmlu_flan_cot_zeroshot_social_sciences
+  - mmlu_flan_cot_zeroshot_humanities

lm_eval/tasks/mmlu/flan_cot_zeroshot/mmlu_abstract_algebra.yaml

-dataset_name: abstract_algebra
-description: 'The following are multiple choice questions (with answers) about abstract
-  algebra.
-
-
-  '
-include: _mmlu_flan_generative_template_yaml
-task: mmlu_flan_cot_zeroshot_abstract_algebra
+"dataset_name": "abstract_algebra"
+"description": "The following are multiple choice questions (with answers) about abstract\
+  \ algebra.\n\n"
+"group": "mmlu_flan_cot_zeroshot_stem"
+"include": "_mmlu_flan_cot_zeroshot_template_yaml"
+"task": "mmlu_flan_cot_zeroshot_abstract_algebra"

lm_eval/tasks/mmlu/flan_cot_zeroshot/mmlu_anatomy.yaml

-dataset_name: anatomy
-description: 'The following are multiple choice questions (with answers) about anatomy.
-
-
-  '
-include: _mmlu_flan_generative_template_yaml
-task: mmlu_flan_cot_zeroshot_anatomy
+"dataset_name": "anatomy"
+"description": "The following are multiple choice questions (with answers) about anatomy.\n\
+  \n"
+"group": "mmlu_flan_cot_zeroshot_stem"
+"include": "_mmlu_flan_cot_zeroshot_template_yaml"
+"task": "mmlu_flan_cot_zeroshot_anatomy"

lm_eval/tasks/mmlu/flan_cot_zeroshot/mmlu_astronomy.yaml

-dataset_name: astronomy
-description: 'The following are multiple choice questions (with answers) about astronomy.
-
-
-  '
-include: _mmlu_flan_generative_template_yaml
-task: mmlu_flan_cot_zeroshot_astronomy
+"dataset_name": "astronomy"
+"description": "The following are multiple choice questions (with answers) about astronomy.\n\
+  \n"
+"group": "mmlu_flan_cot_zeroshot_stem"
+"include": "_mmlu_flan_cot_zeroshot_template_yaml"
+"task": "mmlu_flan_cot_zeroshot_astronomy"

lm_eval/tasks/mmlu/flan_cot_zeroshot/mmlu_business_ethics.yaml

-dataset_name: business_ethics
-description: 'The following are multiple choice questions (with answers) about business
-  ethics.
-
-
-  '
-include: _mmlu_flan_generative_template_yaml
-task: mmlu_flan_cot_zeroshot_business_ethics
+"dataset_name": "business_ethics"
+"description": "The following are multiple choice questions (with answers) about business\
+  \ ethics.\n\n"
+"group": "mmlu_flan_cot_zeroshot_other"
+"include": "_mmlu_flan_cot_zeroshot_template_yaml"
+"task": "mmlu_flan_cot_zeroshot_business_ethics"