Bump wagtail from 2.6.2 to 2.11.8 (#391)

Bumps [wagtail](https://github.com/wagtail/wagtail) from 2.6.2 to 2.11.8.
- [Release notes](https://github.com/wagtail/wagtail/releases)
- [Changelog](https://github.com/wagtail/wagtail/blob/main/CHANGELOG.txt)
- [Commits](https://github.com/wagtail/wagtail/compare/v2.6.2...v2.11.8)

---
updated-dependencies:
- dependency-name: wagtail
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: James Ramm <JamesRamm@users.noreply.github.com>

setup.py

@@ -88,7 +88,7 @@ setup(
     include_package_data=True,
     install_requires=[
         'django==2.2.5',
-        'wagtail==2.6.2',
+        'wagtail==2.11.8',
         'django-countries==5.5',
         'django-extensions==2.2.1',
         'djangorestframework==3.10.3',