Google Doc links in main readme are not shared

[stevula]

Presumably the sharing permissions on these docs should be changed so they are accessible to all New Relic employees or to anyone with the link.

Examples:

• https://github.com/newrelic/nr1-workshop#:~:text=and%20Programmability%20Concepts-,Slides,-Introduction%20to%20the
• https://github.com/newrelic/nr1-workshop#:~:text=the%20nr1%20SDK-,Slides,-Getting%20Started