Bump minor version to 0.3.0
Bump minor version to 0.3.0

This adds a new, backward-compatible feature:
- customizable alt text for screenreaders

Previously, the alt text was always set to the display name.
While this is still the default, instructors can now edit the value
manually.

Stanford-Online/xblock-image-modal,Stanford-Online/xblock-image-modal,Stanford-Online/xblock-image-modal