🧹 chore: add go 1.20 to ci and readmes

[efectn]

Description

Add 1.20 to tests and READMEs

Checklist:

• For new functionalities I follow the inspiration of the express js framework and built them similar in usage
• 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:/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
• If new dependencies exist, I have checked that they are really necessary and agreed with the maintainers/community (we want to have as few dependencies as possible)
• I tried to make my code as fast as possible with as few allocations as possible
• For new code I have written benchmarks so that they can be analyzed and improved

Commit formatting:

Use emojis on commit messages so it provides an easy way of identifying the purpose or intention of a commit. Check out the emoji cheatsheet here: https://gitmoji.carloscuesta.me/