feat: shell completions & auto releasing

[TD-Sky]

Now yazi has shell completion scripts. I package them into the released assets.

The publish actions will be triggered after you create a new tag. Here is a real action:

https://github.com/TD-Sky/yazi/actions/runs/6535605738

And here are the released assets:

https://github.com/TD-Sky/yazi/releases/tag/v0.1.5

[teto]

if the completions can be generated, I wonder if it's worth committing them ? i.e., they can get out of date

[TD-Sky]

if the completions can be generated, I wonder if it's worth committing them ? i.e., they can get out of date

It is not difficult at all to update them.

[sxyazi]

Thank you!