Version of EOSJS
20.0.0-beta3

Describe the bug
A trailing / on the endpoint url will cause eosjs to fail with error Error: Unknown Endpoint

To Reproduce
npm install eosjs@beta node-fetch
then run

const JsonRpc = require('eosjs').JsonRpc
const fetch = require('node-fetch')

const eos = new JsonRpc('http://testnet.telosusa.io/', { fetch })
eos.get_table_rows({json:true, scope: 'priveosrules', code: 'priveosrules',  table: 'nodes', limit:100}).then((data) => {
  console.log(data)
});

Then remove the trailing / on the endpoint and try again.

Expected behavior
The trailing / could be checked for and handled for the developer, or at least a more friendly error message

Desktop (please complete the following information):

• OS: OSX
• Node: v10.15.1
• Browser n/a
• Version n/a