added cors bypass for RSS parser sample

[XiaotianNetlift]

Issue: #61

PR Type

What kind of change does this PR introduce?

• Bugfix

What is the current behavior?

Rss Parser sample can't load feed because of CORS:

Access to fetch at 'https://visualstudiomagazine.com/rss-feeds/news.aspx' from origin 'http://localhost:49996' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

What is the new behavior?

cors-anywhere is used to bypass this.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Pull Request has been submitted to the documentation repository instructions. Link:
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes

Other information

https://github.com/Rob--W/cors-anywhere