Fixing the base value when using iec standard

[avoidwork]

• Fixing the base value when specifying a standard
• Fixes Standard property does not switch base #152

PS C:\Users\jason\Projects\filesize.js\lib> node            
Welcome to Node.js v18.2.0.
Type ".help" for more information.
> const filesize = require('./filesize.es6.js')
undefined
> console.log(filesize(265318, {standard: "jedec"}), filesize(265318, {standard: "iec"}))
259.1 KB 265.32 KiB
undefined

[avoidwork]

This PR wasn't published - version burned; assignment happened after a ternary that uses base.