Support Azure Container Registry

[tomoyamachi]

#195
#198

[olafurnielsen]

I'm using GitHub Actions and using azure/docker-login with service principal auth prior to Dockle and that works fine when referencing a remote image in ACR. Maybe there's a similar action ADO users could take (#195 #198).

Haven't confirmed but using az cli is probably enough:

az acr login -n MyRegistry
# Get an Azure Container Registry access token
# az acr login -n MyRegistry --expose-token

But an implementation for ACR similar to what you have for AWS and GCP would be nice.

This is what I use for GitHub Actions:

    steps:
      - name: Logon to Azure ACR
        uses: azure/docker-login@v1
        with:
          login-server: ${{ vars.ACR_REGISTRY }}
          username: ${{ secrets.ACR_SERVICEPRINCIPAL }}
          password: ${{ secrets.ACR_SERVICEPRINCIPAL_PASSWORD }}

      - name: Run Dockle
        uses: goodwithtech/dockle-action@main
        with:
          image: '${{ vars.ACR_REGISTRY }}/<your_image>:${{ needs.build.outputs.version }}'