Fix: logger color output

[cloudwindy]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.
Explain the details for making this change. What existing problem does the pull request solve?

Fixes logger color output

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

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/

[welcome]

Thanks for opening this pull request! 🎉 Please check out our contributing guidelines. If you need help or want to chat with us, join us on Discord https://gofiber.io/discord

[ReneWerner87]

Do not think that this change fixes a problem
Since I can also unfortunately not get any details from the description

[cloudwindy]

This fixes the problem that because of the following code, the logger middleware does not show colored output in any cases.

if cfg.Output == nil {
	cfg.Output = ConfigDefault.Output
}

// Enable colors if no custom format or output is given
if cfg.Output == nil && checkColorEnable(cfg.Format) {
	cfg.enableColors = true
}

Since cfg.Output will be ConfigDefault.Output in case of it is nil, it does not enable colors.

[ReneWerner87]

Okay I see, we will see if the output writer is the default one

[li-jin-gou]

lgtm

[welcome]

Congrats on merging your first pull request! 🎉 We here at Fiber are proud of you! If you need help or want to chat with us, join us on Discord https://gofiber.io/discord