Charts.h file has executable rights

* [x] I've read, understood, and done my best to follow the [*CONTRIBUTING guidelines](https://github.com/jjatie/Charts/blob/master/CONTRIBUTING.md).

## What did you do?

Build & Archive my app with Charts integrated using Carthage (carthage copy-frameworks)

## What did you expect to happen?

Valid bundle code signature

## What happened instead?

Checking app signature with RB App Checker Lite:

## Charts Environment

**Charts version/Branch/Commit Number: Release 3.4.0**
**Xcode version: 11.2.1**
**Swift version: 5**
**Platform(s) running Charts: macOS 10.15.1**
**macOS version running Xcode: 10.15.1**

## Demo Project
-