Add option to overwrite the zip file

[amenk]

Feature Request

• Yes, I reviewed the contribution guidelines.

Describe your use case and the problem you are facing

Steps to reproduce:

1. wp dist-archive .
2. Add an additional file manually to the dist archive (in real life, my build script added additional files I did not expect)
3. call wp dist-archive . again
4. The additional files are still in the ZIP - it's not created freshly

Describe the solution you'd like

When the dist archive already exists, it seems to not be recreated. An --overwrite option to fully recreate the ZIP would be good.

[GeoJunkie]

If the archive exists, a prompt is given:

Warning: Archive file already exists
/Users/taco/code/wp-cli-dev.zip
Do you want to skip or replace it with a new archive? [s/r]: r
Replacing

Success: Created wp-cli-dev.zip

The Zip file is updated and contains new files I added manually. If this is running inside a script, though, there isn't an option to choose as an option. The code for the prompt could be called/reused for a command-line option.