[Imporve] Set required_approving_review_count to 2

[caicancai]

What changes were proposed in this pull request

Issue Number: close #xxx

Brief change log

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

Does this pull request potentially affect one of the following parts

• Dependencies (does it add or upgrade a dependency): (yes / no)

[wolfboys]

hi caicancai:

Perhaps other projects already have such rules, but each project has its way of collaboration. Introducing rules is to solve problems and bring convenience, not to create obstacles. Currently, there are relatively few committers and PPMC members for Project StreamPark; these committers and PPMC members are not very active either. So I think it's not applicable now.