How to change the push_access_level of protected branches

I have the release* branches as protected with push_access_level as “0” i.e “No One”.
Now i want to update the push_access_level to 40 i.e, “Maintainers”

How do i do this with the help of an API call.
I went through the gitlab api and found the below api call which is allowing only to make branches as protected but not to update them.

Could someone provide me or guide through the correct api call that i need to use.