perf: target Node.js 14 for cjs bundle (main entry)

BREAKING CHANGE: main entry need Node.js>=14 to run, you can build LiquidJS by your own by using ESM entry.

src/liquid-options.ts

@@ -5,7 +5,7 @@ import { FS } from './fs/fs'
 import * as fs from './fs/node'
 import { defaultOperators, Operators } from './render/operator'
 import { filters } from './filters'
-import { assert } from './types'
+import { assert } from './util/assert'
 
 type OutputEscape = (value: any) => string
 type OutputEscapeOption = 'escape' | 'json' | OutputEscape