typescript peer dependency to low for successful compilation

[eps1lon]

Bug Report

• TSLint version: 5.11.0
• TypeScript version: 2.1.6
• Running TSLint via: Node.js API

TSLint cannot be used programmatically in a typescript project with typescript<2.3.0 despite peerDependencies listing typescript >= 2.1.0 i.e. writing a rule for TSLint with typescript@~2.1.0 results in a compilation error:

node_modules/tslint/lib/language/utils.d.ts(52,57): error TS1005: ',' expected.
node_modules/tslint/lib/language/utils.d.ts(52,61): error TS1005: ',' expected.

Cause of this is

tslint/src/language/utils.ts

Line 106 in 9b7574b

export function ancestorWhere<T extends ts.Node = ts.Node>(

Generic argument defaults where added in typescript 2.3.

Unfortunately this method is part of the public API which might cause trouble if we remove the default. Removing this default results in a successful build with 2.1.

Repro: eps1lon/tslint-issue-typescript-peer-version