message: Update security policy
  Add v0.3
diff: @@ -7,7 +7,8 @@ currently being supported with security updates.
  | Version | Supported |
  | ------- | ------------------ |
  -| 0.2.x | :white_check_mark: |
  +| 0.3.x | :white_check_mark: |
  +| 0.2.x | :x: |
  | 0.1.x | :x: |
  ## Reporting a Vulnerability
  