add SHA image for addons

[medyagh]

for more security so if someone pushes the same image tag , we should not accept it, and we should secure it by adding the sha to the image tag

minikube/deploy/addons/registry-creds/registry-creds-rc.yaml.tmpl

Line 21 in 83f9bd1

- image: {{default "upmcenterprises" .ImageRepository}}/registry-creds:1.10

Current tag is pointing at upmcenterprises/registry-creds:1.10@sha256:93a633d4f2b76a1c66bf19c664dbddc56093a543de6d54320f19f585ccd7d605

[jiefenghe]

/assign