switch docker documentation to GHCR (#4885)

For parity, also remove major version suffix from GHCR packages.

Signed-off-by: Spencer Schrock <sschrock@google.com>

Author: spencerschrock

.github/workflows/publishimage.yml

@@ -65,4 +65,4 @@ jobs:
        uses: sigstore/cosign-installer@faadad0cce49287aee09b3a48701e75088a2c6ad
      - name: Sign image
        run: |
-          cosign sign --yes ghcr.io/${{github.repository_owner}}/scorecard/v5:${{ github.sha }}
+          cosign sign --yes ghcr.io/${{github.repository_owner}}/scorecard:${{ github.sha }}

Makefile

@@ -383,10 +383,10 @@ $(KOCACHE_PATH):
 
 scorecard-ko: | $(KO) $(KOCACHE_PATH)
 	KO_DATA_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-			   KO_DOCKER_REPO=${KO_PREFIX}/${IMAGE_NAME}
+			   KO_DOCKER_REPO=ghcr.io/ossf/scorecard \
 			   LDFLAGS="$(LDFLAGS)" \
 			   KO_CACHE=$(KOCACHE_PATH) \
-			   $(KO) build -B \
+			   $(KO) build --bare \
 			   --sbom=none \
 			   --platform=$(PLATFORM) \
 			   --tags latest,$(GIT_VERSION),$(GIT_HASH) \

README.md

@@ -231,13 +231,13 @@ Language: You must have GoLang installed to run Scorecard
 `scorecard` is available as a Docker container:
 
 ```shell
-docker pull gcr.io/openssf/scorecard:stable
+docker pull ghcr.io/ossf/scorecard:latest
 ```
 
 To use a specific scorecard version (e.g., v3.2.1), run:
 
 ```shell
-docker pull gcr.io/openssf/scorecard:v3.2.1
+docker pull ghcr.io/ossf/scorecard:v3.2.1
 ```
 
 ##### Standalone
@@ -410,13 +410,13 @@ Check scores:
 The `GITHUB_AUTH_TOKEN` has to be set to a valid [token](#Authentication)
 
 ```shell
-docker run -e GITHUB_AUTH_TOKEN=token gcr.io/openssf/scorecard:stable --show-details --repo=https://github.com/ossf/scorecard
+docker run -e GITHUB_AUTH_TOKEN=token ghcr.io/ossf/scorecard:latest --show-details --repo=https://github.com/ossf/scorecard
 ```
 
 To use a specific scorecard version (e.g., v3.2.1), run:
 
 ```shell
-docker run -e GITHUB_AUTH_TOKEN=token gcr.io/openssf/scorecard:v3.2.1 --show-details --repo=https://github.com/ossf/scorecard
+docker run -e GITHUB_AUTH_TOKEN=token ghcr.io/ossf/scorecard:v3.2.1 --show-details --repo=https://github.com/ossf/scorecard
 ```
 
 ##### Showing Detailed Results