In src/schemas/execute.yaml, Withdrawals is not a valid `jsonschema`

[smoyer64]

The current schema is

execution-apis/src/schemas/execute.yaml

Lines 147 to 152 in de87e24

	Withdrawals:
	title: Withdrawals made by validators
	description: This array can have a maximum length of 16.
	type: array
	items:
	- $ref: '#/components/schemas/Withdrawal'

. This should instead be:

 Withdrawals: 
   title: Withdrawals made by validators 
   description: This array can have a maximum length of 16. 
   type: array 
   items: 
     $ref: '#/components/schemas/Withdrawal'