Bump wagtail in /{{cookiecutter.project_name}}/src/requirements

Bumps [wagtail](https://github.com/wagtail/wagtail) from 6.1.3 to 6.3.
- [Release notes](https://github.com/wagtail/wagtail/releases)
- [Changelog](https://github.com/wagtail/wagtail/blob/main/CHANGELOG.txt)
- [Commits](wagtail/wagtail@v6.1.3...v6.3)

---
updated-dependencies:
- dependency-name: wagtail
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

{{cookiecutter.project_name}}/src/requirements/base.txt

@@ -4,7 +4,7 @@ gevent==24.2.1
 psycopg==3.2.1
 python-dotenv==1.0.1
 sentry_sdk[django]==2.13.0
-wagtail==6.1.3
+wagtail==6.3
 wagtail-meta-preview==4.1.0
 wagtail_headless_preview==0.8.0
 whitenoise==6.7.0