doc/Changelog.org: Release 0.5.0

Fixes abo-abo#271

avy.el (avy--overlay): Fix interaction with goto-address-mode

The other overlay has no priority, but sets a face. That face is
overridden by the avy overlay (which has priority).

Fixes abo-abo/ace-link#24

Bump version to 0.3.0

* doc/Changelog.org: Start tracking the changes in each new version.

Bump version