chore: update dag-pb (#79)

Author: achingbrain

package.json

@@ -54,7 +54,7 @@
     "debug": "^4.1.0",
     "fnv1a": "^1.0.1",
     "interface-datastore": "^3.0.3",
-    "ipld-dag-pb": "^0.21.0",
+    "ipld-dag-pb": "^0.22.1",
     "it-length": "^1.0.1",
     "multibase": "^4.0.1",
     "multicodec": "^3.0.1",