fix: reduce seqno to 8 bytes (#31)

Author: mpetrunic

src/utils.js

@@ -12,7 +12,7 @@ exports = module.exports
  * @private
  */
 exports.randomSeqno = () => {
-  return crypto.randomBytes(20)
+  return crypto.randomBytes(8)
 }
 
 /**

test/utils.spec.js

@@ -10,8 +10,8 @@ describe('utils', () => {
     const first = utils.randomSeqno()
     const second = utils.randomSeqno()
 
-    expect(first).to.have.length(20)
-    expect(second).to.have.length(20)
+    expect(first).to.have.length(8)
+    expect(second).to.have.length(8)
     expect(first).to.not.eql(second)
   })