Feature: allow overwriting secret, instead of editing it

[eyJhb]

The use case is,that I have a password stored in a secret file for e.g. my murmur server, which I will rotate on a regular basis.
However, I have no need for to decrypt it before I change the content of the file, I just want to overwrite it, like it was a completely new file.
It would be nice, if it was possible to do with the CLI agenix provides.

I realise that a current workaround would just be to rename tho file, or delete it before using the -e option.

I would expect it to work as follows:

1. agenix --overwrite murmur-password.age
2. Open editor/copy from stdin
3. If input is non-zero, then overwrite, otherwise keep existing file.

Could that maybe be of interest?