Support specifying image digests

.gitlab/release-notes.md.template

templates/apply.yml

templates/custom-command.yml

templates/destroy.yml

templates/fmt.yml

templates/full-pipeline.yml

templates/graph.yml

templates/job-templates.yml

templates/plan.yml

templates/test.yml

templates/validate-plan-apply.yml

templates/validate-plan-destroy.yml

templates/validate-plan.yml

templates/validate.yml