chore(deps): update dependency typescript to v3.1.1 (#458)

This PR contains the following updates:

| Package | Type | Update | Change | References |
|---|---|---|---|---|
| typescript | devDependencies | minor | `3.0.3` -> `3.1.1` | [homepage](http://typescriptlang.org/), [source](https://renovatebot.com/gh/Microsoft/TypeScript) |

---

### Release Notes

<details>
<summary>Microsoft/TypeScript</summary>

### [`v3.1.1`](https://renovatebot.com/gh/Microsoft/TypeScript/releases/v3.1.1)

[Compare Source](https://renovatebot.com/gh/Microsoft/TypeScript/compare/v3.0.3...v3.1.1)

For release notes, check out the [release announcement](https://blogs.msdn.microsoft.com/typescript/announcing-typescript-3-1/) 

For new features, check out the [What's new in TypeScript 3.1](https://renovatebot.com/gh/Microsoft/TypeScript/wiki/What's-new-in-TypeScript#typescript-31).

For breaking changes, check out the [Breaking changes in TypeScript 3.1](https://renovatebot.com/gh/Microsoft/TypeScript/wiki/Breaking-Changes#typescript-31) page.

For the complete list of fixed issues, check out the [fixed issues query for Typescript 3.1](https://renovatebot.com/gh/Microsoft/TypeScript/issues?q=is%3Aissue+milestone%3A%22TypeScript+3.1%22+label%3A%22fixed%22+).

Download:

-   [npm](https://www.npmjs.com/package/typescript)
-   [Visual Studio 2017](https://www.microsoft.com/en-us/download/details.aspx?id=55258) ([Select new version in project options](https://renovatebot.com/gh/Microsoft/TypeScript/wiki/Updating-TypeScript-in-Visual-Studio-2017))
-   [NuGet package](https://www.nuget.org/packages/Microsoft.TypeScript.MSBuild/3.1.0)

Special thanks to all contributors to this release:

-   Alexander Tarasyuk
-   Anders Hejlsberg
-   Andrew Casey
-   Andy Hanson
-   Benjamin Lichtman
-   Brian Terlson
-   [@&#8203;csigs](https://renovatebot.com/gh/csigs)
-   Dan Rollo
-   Daniel Imms
-   Daniel Rosenwasser
-   David Sherret
-   Elizabeth Dinella
-   Frederico Bittencourt
-   Jack Williams
-   James Keane
-   Jordi Oliveras Rovira
-   Klaus Meinhardt
-   Martin Probst
-   Matt McCutchen
-   Mine Starks
-   Minh Nguyen
-   Nathan Day
-   Mohamed Hegazy
-   Nathan Shively-Sanders
-   Ron Buckton
-   Rhys van der Waerden
-   Ryan Cavanaugh
-   Sam Lanning
-   Sheetal Nandi
-   Wenlu Wang
-   Wesley Wigham
-   Tim Schaub

</details>

---

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---

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Author: renovate[bot]

package.json

@@ -63,7 +63,7 @@
     "semantic-release": "15.9.17",
     "tslint": "5.11.0",
     "tslint-config-prettier": "1.15.0",
-    "typescript": "3.0.3"
+    "typescript": "3.1.1"
   },
   "keywords": [
     "behavior-smooth",

src/index.ts

@@ -64,7 +64,8 @@ function scrollIntoView<T>(
 function scrollIntoView(target: Element, options?: Options | boolean): void
 function scrollIntoView<T>(target: Element, options?: Options<T> | boolean) {
   // Browsers treats targets that aren't in the dom as a no-op
-  const scrollingElement = document.scrollingElement || document.documentElement
+  const scrollingElement = (document.scrollingElement ||
+    document.documentElement) as Element
   const targetIsDetached =
     target !== scrollingElement && !scrollingElement.contains(target)
 

src/types.ts

@@ -17,7 +17,7 @@ export interface Options {
 
 // Custom behavior, not in any spec
 export type CustomScrollBoundaryCallback = (parent: Element) => boolean
-export type CustomScrollBoundary = Element | CustomScrollBoundaryCallback
+export type CustomScrollBoundary = Element | CustomScrollBoundaryCallback | null
 export interface CustomScrollAction {
   el: Element
   top: number

yarn.lock

@@ -6552,10 +6552,10 @@ typescript-compiler@^1.4.1-2:
   resolved "https://registry.yarnpkg.com/typescript-compiler/-/typescript-compiler-1.4.1-2.tgz#ba4f7db22d91534a1929d90009dce161eb72fd3f"
   integrity sha1-uk99si2RU0oZKdkACdzhYety/T8=
 
-typescript@3.0.3:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.0.3.tgz#4853b3e275ecdaa27f78fda46dc273a7eb7fc1c8"
-  integrity sha512-kk80vLW9iGtjMnIv11qyxLqZm20UklzuR2tL0QAnDIygIUIemcZMxlMWudl9OOt76H3ntVzcTiddQ1/pAAJMYg==
+typescript@3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.1.1.tgz#3362ba9dd1e482ebb2355b02dfe8bcd19a2c7c96"
+  integrity sha512-Veu0w4dTc/9wlWNf2jeRInNodKlcdLgemvPsrNpfu5Pq39sgfFjvIIgTsvUHCoLBnMhPoUA+tFxsXjU6VexVRQ==
 
 typescript@~2.4.2:
   version "2.4.2"