Add --output-file option

[bitfield]

When automating sops operations, it would be useful to be able to specify an output file, rather than redirecting stdout. Also, a shell isn't always available to do the redirecting, for example when running sops as a Cloud Build step to decrypt application credentials during a deploy.

[hellozee]

Would love to give it a shot if no one has taken it yet

[jvehent]

Go for it!

[hellozee]

cool