Bump snok/container-retention-policy from 2.2.1 to 3.0.0

Bumps [snok/container-retention-policy](https://github.com/snok/container-retention-policy) from 2.2.1 to 3.0.0.
- [Release notes](https://github.com/snok/container-retention-policy/releases)
- [Commits](snok/container-retention-policy@b56f4ff...4f22ef8)

---
updated-dependencies:
- dependency-name: snok/container-retention-policy
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/cleanup.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Delete untagged images older than 1 week
-        uses: snok/container-retention-policy@b56f4ff7539c1f94f01e5dc726671cd619aa8072 # v2.2.1
+        uses: snok/container-retention-policy@4f22ef80902ad409ed55a99dc5133cc1250a0d03 # v3.0.0
         with:
           account-type: org
           org-name: ministryofjustice
@@ -23,7 +23,7 @@ jobs:
           token: ${{ secrets.BOT_GITHUB_PACKAGES_TOKEN }}
 
       - name: Delete all images older than a month that aren't currently deployed
-        uses: snok/container-retention-policy@b56f4ff7539c1f94f01e5dc726671cd619aa8072 # v2.2.1
+        uses: snok/container-retention-policy@4f22ef80902ad409ed55a99dc5133cc1250a0d03 # v3.0.0
         with:
           account-type: org
           org-name: ministryofjustice