release: bump version to v0.7.0

Updates package.json and artifacthub-pkg.yml for the v0.7.0 release.
Includes all changes since v0.6.0:
- RBAC fix for Polaris dashboard proxy access (PR #22)
- Settings test selector fix (PR #22)
- Package name correction from solaris to polaris (PR #26)
- E2E preflight check (PR #24)
- Missing test dependencies (PR #28)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "headlamp-polaris",
-  "version": "0.6.0",
+  "version": "0.7.0",
   "description": "Headlamp plugin for Fairwinds Polaris audit results",
   "repository": {
     "type": "git",