Release v0.8.1

finalise 0.8.0 (IBM#172)

add support for sigstore (IBM#111)

* crd and config file

* works end-end

* functional

* type fix

* simple policy only

* typo

support for redhat simple signature verification (IBM#84)

* save

* wip-save

* unused

* wip-2

* wip

* wip

* pr check

* makefile fmt

* no dep on gpgme

* vet

* fix test invoke

* trust and simple concurrenltly

* review issues

* ease local testing

* improve ut tests

* e2e.simple

* README less DCT specific

* multiple simple policies and tests

* keys from secrets

* doc typos, code cleanliness

release

Bump version to 0.5.1 (IBM#43)

Add support for icr.io