Add ko targets for the webhook image. (#630)

Signed-off-by: Dan Lorenc <dlorenc@google.com>

.github/workflows/build.yaml

@@ -49,4 +49,4 @@ jobs:
       - name: creds
         run: gcloud auth configure-docker --quiet
       - name: container
-        run: echo -n "${{secrets.COSIGN_PASSWORD}}" | KO_DOCKER_REPO=gcr.io/projectsigstore/cosign/ci/cosign make sign-container
+        run: echo -n "${{secrets.COSIGN_PASSWORD}}" | KO_PREFIX=gcr.io/projectsigstore/cosign/ci make sign-container

Makefile

@@ -83,20 +83,26 @@ clean:
 .PHONY: ko
 ko:
 	# We can't pass more than one LDFLAG via GOFLAGS, you can't have spaces in there.
-	CGO_ENABLED=0 GOFLAGS="-ldflags=-X=$(PKG).gitCommit=$(GIT_HASH)" ko publish --bare \
+	KO_DOCKER_REPO=${KO_PREFIX}/cosign CGO_ENABLED=0 GOFLAGS="-ldflags=-X=$(PKG).gitCommit=$(GIT_HASH)" ko publish --bare \
 		--tags $(GIT_VERSION) --tags $(GIT_HASH) \
 		github.com/sigstore/cosign/cmd/cosign
+
+	# cosigned
+	KO_DOCKER_REPO=${KO_PREFIX}/cosigned CGO_ENABLED=0 GOFLAGS="-ldflags=-X=$(PKG).gitCommit=$(GIT_HASH)" ko publish --bare \
+		--tags $(GIT_VERSION) --tags $(GIT_HASH) \
+		github.com/sigstore/cosign/cmd/cosign/webhook
 
 .PHONY: ko-local
 ko-local:
 	# We can't pass more than one LDFLAG via GOFLAGS, you can't have spaces in there.
-	CGO_ENABLED=0 GOFLAGS="-ldflags=-X=$(PKG).gitCommit=$(GIT_HASH)" ko publish --bare \
+	KO_DOCKER_REPO=${KO_PREFIX}/cosign CGO_ENABLED=0 GOFLAGS="-ldflags=-X=$(PKG).gitCommit=$(GIT_HASH)" ko publish --bare \
 		--tags $(GIT_VERSION) --tags $(GIT_HASH) --local \
 		github.com/sigstore/cosign/cmd/cosign
 
 .PHONY: sign-container
 sign-container: ko
-	cosign sign -key .github/workflows/cosign.key -a GIT_HASH=$(GIT_HASH) ${KO_DOCKER_REPO}:$(GIT_HASH)
+	cosign sign -key .github/workflows/cosign.key -a GIT_HASH=$(GIT_HASH) ${KO_PREFIX}/cosign:$(GIT_HASH)
+	cosign sign -key .github/workflows/cosign.key -a GIT_HASH=$(GIT_HASH) ${KO_PREFIX}/cosigned:$(GIT_HASH)
 
 # used when releasing together with GCP CloudBuild
 .PHONY: release