Issue #3625318: Back to DEV

Back to DEV after the 1.0.3 release.

• composer.json: version back to 1.0.x-dev, and every Varbase base recipe and drupal/vartheme_bs5 back to their dev branches.
• README.md: version badge back to 1.0.x-dev.

CHANGELOG.md is left alone: the 1.0.3 entry stays and the Unreleased heading is already in place above it.

Released: varbase_starter 1.0.3, tag 1.0.3 at eb392841, pipeline 973313, 31 jobs, 0 failed.

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
• Automated unit testing coverage
• Automated functional testing coverage
• UX/UI designer responsibilities
• Readability
• Accessibility
• Performance
• Security
• Developer Documentation
• User Guide Documentation
• Reviewed by a human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release