bug: use wrong _useWorkers value when not supported

[kybarg]

Seems like line 680 should be, otherwise it doen't work and makes no sense

_useWorkers = true

bigint-crypto-utils/src/js/index.js

Lines 667 to 684 in 902e9fc

	let _useWorkers = false // The following is just to check whether we can use workers
	/* eslint-disable no-lone-blocks */
	if (!process.browser) { // Node.js
	try {
	require.resolve('worker_threads')
	_useWorkers = true
	} catch (e) {
	/* istanbul ignore next */
	console.log(`[bigint-crypto-utils] WARNING:
	This node version doesn't support worker_threads. You should enable them in order to greatly speedup the generation of big prime numbers.
	· With Node >=11 it is enabled by default (consider upgrading).
	· With Node 10, starting with 10.5.0, you can enable worker_threads at runtime executing node --experimental-worker `)
	/* istanbul ignore next */
	_useWorkers = true
	}
	} else { // Native JS
	if (self.Worker) _useWorkers = true
	}

[juanelas]

Than you for reporting the bug! Now it is fixed.