Add synth metadata. (#6560)

Author: yoshi-automation

packages/google-cloud-asset/synth.metadata

@@ -0,0 +1,27 @@
+{
+  "sources": [
+    {
+      "git": {
+        "name": "googleapis",
+        "remote": "https://github.com/googleapis/googleapis.git",
+        "sha": "5a57f0c13a358b2b15452bf2d67453774a5f6d4f",
+        "internalRef": "221837528"
+      }
+    },
+    {
+      "git": {
+        "name": "googleapis-private",
+        "remote": "https://github.com/googleapis/googleapis-private.git",
+        "sha": "6aa8e1a447bb8d0367150356a28cb4d3f2332641",
+        "internalRef": "221340946"
+      }
+    },
+    {
+      "generator": {
+        "name": "artman",
+        "version": "0.16.0",
+        "dockerImage": "googleapis/artman@sha256:90f9d15e9bad675aeecd586725bce48f5667ffe7d5fc4d1e96d51ff34304815b"
+      }
+    }
+  ]
+}