0.6.0-preview

Updated:

• Replaced test VM to use gtx1080
• Updated README.md
• Added LICENSE.md under the project folder.
• Shader version properties in all the render pipeline shaders.

Fixed:

• Some unnecessary classes were public.
• URP: a depth output issue later then 10.0.x. (Thanks to riina)
• Typos in README.md
• promotion test issues.
• no .sample.json files under each render-pileline sample folder.