Release Version 0.5.0

[beeme1mr]

Release checklist:

• [x] Release spec v0.5.0
• [x] Update spec badge on the org readme
• [x] Create issues in the SDK repos containing the new requirements
  • Java
  • Python
  • JS
  • .NET
  • Go
  • PHP
• [x] docs

Spec v0.5.0 badge