chore(release): 0.3.0 (#22)

## Summary
Bump the version to 0.3.0 for the next extension release: sound themes, in-app dialogs, notifications that work across browsers and in the extension.

## Testing
- Lint, typecheck, unit tests and build pass.

Author: ttncode

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "boost-focus-timer",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "private": true,
   "description": "A calm focus timer with to-dos, habits, goals and session history. Runs in the browser or as a browser extension; all data stays local.",
   "author": "ttncode",