🧹 update: add methods configuration for cache middleware

[efectn]

Description

We may need to cache some methods according to our needs. I think we should be able to set methods to cache.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation - https://github.com/gofiber/docs for https://docs.gofiber.io/
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I tried to make my code as fast as possible with as few allocations as possible

[ReneWerner87]

thanks @efectn
LGTM