Update zig version 0.13.0

[42LM]

Hey there @softprops 👋,
i just happened to find this lib today and it was exactly what i was searching for without much overhead. First of all thanks for doing this 😎!

I am currently running zig v0.13.0 and everything works for me. So i decided to create this small PR to update to version 0.13.0. Not much changes needed here, but trying to give something back 😅.

What i have done:

• Add matrix for zig versions 0.12.0 and 0.13.0 in the githubci test
• Add new .zig-cache to .gitignore
• Adjust zig version logo to just show both versions without link:
• Add paths to build.zig, build.zig.zon and src to the build.zig.zon file
• Adjust the README.md:
  • New and easier zig fetch command for 0.13.0
  • Adjust outdated documentation link of 0.11.0 to point to 0.13.0
• Missing new line at end of file in .gitignore

Have a great start of the week 🍀

[softprops]

This looks great to me. Thanks!