fix: enable provenance for extension images

exports a manifest list which is required for `imager`

Signed-off-by: Tom Plant <tom@tplant.com.au>

.github/workflows/ci.yaml

@@ -71,6 +71,7 @@ jobs:
         if: github.event_name != 'pull_request'
         env:
           USERNAME: ${{ github.repository_owner }}
+          CI_ARGS: --provenance=true
         run: |
           make  PUSH=true
       - name: Push nonfree

Makefile

@@ -201,7 +201,7 @@ internal/extensions/descriptions.yaml: internal/extensions/image-digests
 	@echo "Generating image descriptions..."
 	@echo -n "" > internal/extensions/descriptions.yaml
 	@for image in $(shell cat internal/extensions/image-digests); do \
-	  crane export $$image - | tar x -O --occurrence=1 manifest.yaml | yq -r ". += {\"$$image\": {\"author\": .metadata.author, \"description\": .metadata.description}} | del(.metadata, .version)" - >> internal/extensions/descriptions.yaml; \
+	  crane export $$image --platform linux/arm64 - | tar x -O --occurrence=1 manifest.yaml | yq -r ". += {\"$$image\": {\"author\": .metadata.author, \"description\": .metadata.description}} | del(.metadata, .version)" - >> internal/extensions/descriptions.yaml; \
 	done
 
 .PHONY: sign-images