schema: metadata at the top level

Allows a new object under the top-level key `metadata` which contains a
`generators` property. This property is a list of all generators involved
in the creation of a manifest.

Each generator can add its name and version to this list.

Signed-off-by: Simon de Vlieger <supakeen@redhat.com>

schemas/osbuild2.json

@@ -19,6 +19,9 @@
       "enum": [
         "2"
       ]
+    },
+    "metadata": {
+      "$ref": "#/definitions/metadata"
     }
   },
   "definitions": {
@@ -83,6 +86,31 @@
         }
       }
     },
+    "metadata": {
+      "title": "Metadata information for a manifest",
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "generators": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "additionalProperties": false,
+            "required": [
+              "name"
+            ],
+            "properties": {
+              "name": {
+                "type": "string"
+              },
+              "version": {
+                "type": "string"
+              }
+            }
+          }
+        }
+      }
+    },
     "mounts": {
       "title": "Collection of mount points for a stage",
       "type": "array",

test/data/manifests/fedora-boot.json

@@ -1,5 +1,13 @@
 {
   "version": "2",
+  "metadata": {
+    "generators": [
+      {
+        "name": "osbuild-mpp",
+        "version": "unknown"
+      }
+    ]
+  },
   "pipelines": [
     {
       "runner": "org.osbuild.fedora39",

test/data/manifests/fedora-boot.mpp.yaml

@@ -2,6 +2,10 @@
 # Noticed the org.osbuild.test that was added.
 
 version: '2'
+metadata:
+  generators:
+    - name: osbuild-mpp
+      version: unknown
 pipelines:
   - mpp-import-pipelines:
       path: fedora-vars.ipp.yaml