Don't use default parameters for IE compatibility

src/index.js

@@ -19,7 +19,8 @@ const binaryToBytes = binaryString => Buffer.from(
 
 const randomNumberBetween = (min, max) => Math.floor(parseInt(randomBytes(1).toString('hex'), 16) / 256 * (max - min + 1) + min);
 
-const dogeSeed = (bits = 128) => {
+const dogeSeed = (bits) => {
+  bits = bits || 128;
   if (bits <= 0 || bits % 8 !== 0) {
     throw TypeError('bits must be divisible by 8');
   }