fix: ensure all types referenced in the actors registry are CBOR marshallable

[rvagg]

DRAFT for now unfortunately. See filecoin-project/go-state-types#397 that this depends on. We have to:

• Get a fix into cbor-gen and get it released
• Update cbor-gen and re-gen the types in feat: cbor encoding of all referenced param & return types go-state-types#397
• Release a go-state-types
• Update here

[rvagg]

Background for this is in Slack:

curl -X POST https://api.calibration.node.glif.io/rpc/v1 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "Filecoin.StateDecodeParams",
    "params": [
      "t03", // CRON ACTOR
      1, // METHOD_NUM 1
      "gYGCQwDpBwE=", 
      [
        { "/": "bafy2bzacedpaiat6lkx7bfvoibvfpx62sce3winwb5dmnkdsszgva6pguc5oy" },
        { "/": "bafy2bzacebuyutgmfr5l6e2k4rnqtpdmj7dby4vo46ai63qfqinkxx5zdmie6" }
      ]
    ],
    "id": 1
  }'

{"error":{"code":1,"message":"fatal error calling 'Filecoin.StateDecodeParams': panic in rpc method 'Filecoin.StateDecodeParams': interface conversion: *cron.ConstructorParams is not typegen.CBORUnmarshaler: missing method UnmarshalCBOR"},"id":1,"jsonrpc":"2.0"}

[rvagg]

ugh!