Transfer axis label colors

[frutti93]

As of now the color of axis labels is not considered in the tikz output. This small change fixes this.

[frutti93]

I am going to fix the tests next week ;)

[nschloe]

What are these dockerfiles?

[frutti93]

Sorry, my mistake. I develop in containers and usually keep the dockerfiles in my gitignore. Obviously forgot it this time. I just removed them.

[nschloe]

There is another weird file.

[frutti93]

Removed. But this is nothing that is introduced by my changes. This file is reproducibly generated by running tox, even on main. Thats why i left it there. I added it to the gitignore so no one else commits it by mistake.

[nschloe]

... and another one.

[frutti93]

... and again, these file are generated by running the unittests in general, they have nothing to do with this PR.

[nschloe]

What's the label color by default?

[frutti93]

Tikz and matplotlib use 'black', however, for matplotlib it depends on the chosen plot style.

[nschloe]

I understand. I would probably lean towards "explicit is better than implicit" nowadays, too, but tikzplotlib has made a choice years ago to not include code that's default anyway. The idea was to keep the output TeX file reasonably lean. I would hence suggest to only include the color spec if it's not black.

[nschloe]

LGTM now. Thanks!