AP: Tag specific version along with migrate

- AP migration should be tagged along with the main AP instance to keep things in line
  - Renovate will now group them together so it bumps them at the same time in the same PR/commit etc to keep things aligned
- Moving to specific version pinning as well to make the renovate diffs clearer

.github/renovate.json5

@@ -9,6 +9,18 @@
 	],
 	suppressNotifications: ["prIgnoreNotification"],
 	packageRules: [
+		{
+			description: "Group ActivityPub containers together",
+			matchDatasources: ["docker", "github-tags", "docker-compose"],
+			matchPackageNames: [
+				"ghcr.io/tryghost/activitypub",
+				"ghcr.io/tryghost/activitypub-migrations",
+			],
+			groupName: "ActivityPub",
+			groupSlug: "activitypub",
+			additionalBranchPrefix: "",
+			separateMinorPatch: false,
+		},
 		{
 			description: "Auto-merge initial digest pinning",
 			matchDatasources: ["docker", "github-tags"],