feat: add Filecoin multicodecs

* fil-commitment-unsealed
* fil-commitment-sealed

Ref: https://github.com/multiformats/multicodec/pull/161
Ref: https://github.com/multiformats/multicodec/pull/172

cid.go

@@ -75,6 +75,8 @@ const (
 	DecredTx              = 0xe1
 	DashBlock             = 0xf0
 	DashTx                = 0xf1
+	FilCommitmentUnsealed = 0xf101
+	FilCommitmentSealed   = 0xf102
 )
 
 // Codecs maps the name of a codec to its type
@@ -102,6 +104,8 @@ var Codecs = map[string]uint64{
 	"decred-tx":               DecredTx,
 	"dash-block":              DashBlock,
 	"dash-tx":                 DashTx,
+	"fil-commitment-unsealed": FilCommitmentUnsealed,
+	"fil-commitment-sealed":   FilCommitmentSealed,
 }
 
 // CodecToStr maps the numeric codec to its name
@@ -127,6 +131,8 @@ var CodecToStr = map[uint64]string{
 	DecredTx:              "decred-tx",
 	DashBlock:             "dash-block",
 	DashTx:                "dash-tx",
+	FilCommitmentUnsealed: "fil-commitment-unsealed",
+	FilCommitmentSealed:   "fil-commitment-sealed",
 }
 
 // tryNewCidV0 tries to convert a multihash into a CIDv0 CID and returns an

cid_test.go

@@ -38,6 +38,8 @@ var tCodecs = map[uint64]string{
 	DecredTx:              "decred-tx",
 	DashBlock:             "dash-block",
 	DashTx:                "dash-tx",
+	FilCommitmentUnsealed: "fil-commitment-unsealed",
+	FilCommitmentSealed:   "fil-commitment-sealed",
 }
 
 func assertEqual(t *testing.T, a, b Cid) {