fix(blob): use proper share.MaxShareVersion const (#64)

We were comparing against incorrect const (`math.MaxUint8`) but error message refers to the proper (`share.MaxShareVersion`).

Sadly we cannot import `shares` package in `blob` due to cyclic dependency, adding comment for the future. Also, removed useless `fmt` alias for `fmt` package.

blob/blob.go

@@ -5,8 +5,7 @@ package blob
 import (
 	"bytes"
 	"errors"
-	fmt "fmt"
-	math "math"
+	"fmt"
 	"sort"
 
 	"github.com/celestiaorg/go-square/namespace"
@@ -24,6 +23,9 @@ const ProtoBlobTxTypeID = "BLOB"
 // decoding binaries that are not actually IndexWrappers.
 const ProtoIndexWrapperTypeID = "INDX"
 
+// MaxShareVersion is the maximum value a share version can be. See: [shares.MaxShareVersion].
+const MaxShareVersion = 127
+
 // New creates a new coretypes.Blob from the provided data after performing
 // basic stateless checks over it.
 func New(ns namespace.Namespace, blob []byte, shareVersion uint8) *Blob {
@@ -51,7 +53,7 @@ func (b *Blob) Validate() error {
 	if len(b.NamespaceId) != namespace.NamespaceIDSize {
 		return fmt.Errorf("namespace id must be %d bytes", namespace.NamespaceIDSize)
 	}
-	if b.ShareVersion > math.MaxUint8 {
+	if b.ShareVersion > MaxShareVersion {
 		return errors.New("share version can not be greater than MaxShareVersion")
 	}
 	if b.NamespaceVersion > namespace.NamespaceVersionMax {