Bump ministryofjustice/github-actions from 18.2.4 to 18.3.1 (#151)

Author: dependabot[bot]

.github/workflows/images.yml

@@ -147,7 +147,7 @@ jobs:
 
       - name: Set Up Container Structure Test
         id: setup_container_structure_test
-        uses: ministryofjustice/github-actions/setup-container-structure-test@e08cbcac12ec9c09d867ab2b803d4ea1a87300ad # v18.2.4
+        uses: ministryofjustice/github-actions/setup-container-structure-test@9f2e1064389dae6ca4098470b933da7042675e59 # v18.3.1
 
       - name: Set Up QEMU
         id: setup_qemu