Use the same key when restore from cache

[noxasch]

Hi thanks for maintaining this fork, but I'm curious do you intend to fix this bug or is this a feature ?

Describe the bug Currently this fork share the same bug as the original fork where cache are not shared across action due to different cache key are being use.

Can refer the original comment here https://github.com/satackey/action-docker-layer-caching/issues/169#issuecomment-1217408538

To Reproduce

1. Run an action.
2. Run another separate action after it finish.
3. The cache cannot be restore due to layer- is not appended to the restore key but added during caching process to the key.

[jpribyl]

Ah interesting, thanks for raising this @noxasch ! It looks like there is a workaround suggested in the comment you linked, do you think it would suffice to update the README in order to document that or did you have an idea for a more robust fix here?