core.setOutput should support null separated values

[sk-]

Describe the enhancement
Currently setOutput escapes new lines, but it would be great if it also escaped the null character so that one can use it to separate array outputs.

Additional information
Right now I'm using a new line to separate the array entries, but that means that if the entries have whitespaces we need to use the following:

echo "${{ steps.changed-files.outputs.files }}" | tr '\n' '\0' | xargs -0 ls -lh

However is setOutput supported null separated bytes, we could just do:

echo "${{ steps.changed-files.outputs.files }}" | xargs -0 ls -lh