RLE example does not work - 'bitWidth' does not exist in type 'FieldDefinition'

[benjamin-brady]

Steps to reproduce

• Install parquetjs from npm
• Try to compile the following code from the README:

import parquetjs from "@dsnp/parquetjs"
var schema1 = new parquetjs.ParquetSchema({
age: { type: 'UINT_32', encoding: 'RLE', bitWidth: 7 },
});

Expected behaviour

It should at least compile.

Actual behaviour

Error because there is no bitWidth property on the FieldDefinition type.

Object literal may only specify known properties, and 'bitWidth' does not exist in type 'FieldDefinition'.ts(2353)
declare.d.ts(14, 5): 
The expected type comes from this index signature.
(property) bitWidth: number

[wilwade]

@benjamin-brady Looks like there was an upstream doc issue.

tldr: Use typeLength instead of bitWidth

ironSource#100

I'll put up a PR to fix it with a simple test as well.