chore(deps): bump mistune from 0.7.1 to 0.8.1

Bumps [mistune](https://github.com/lepture/mistune) from 0.7.1 to 0.8.1.
- [Release notes](https://github.com/lepture/mistune/releases)
- [Changelog](https://github.com/lepture/mistune/blob/v0.8.1/CHANGES.rst)
- [Commits](lepture/mistune@v0.7.1...v0.8.1)

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

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

Author: dependabot[bot]

requirements.txt

@@ -12,7 +12,7 @@ gunicorn==19.6.0
 jieba==0.38
 Jinja2==3.0.1
 marshmallow==2.16.3
-mistune==0.7.1
+mistune==0.8.1
 nose==1.3.7
 pypinyin==0.16.1
 python-dateutil==2.6.0

setup.py

@@ -22,7 +22,7 @@
         'Flask-Alembic==2.0.1', 'Flask-SQLAlchemy==2.5.1',
         'Flask-Themes2==1.0.0', 'SQLAlchemy-Utils==0.37.8', 'gevent==21.8.0',
         'gunicorn==19.6.0', 'jieba==0.38', 'Jinja2==3.0.1',
-        'marshmallow==2.16.3', 'mistune==0.7.1', 'nose==1.3.7',
+        'marshmallow==2.16.3', 'mistune==0.8.1', 'nose==1.3.7',
         'pypinyin==0.16.1', 'python-dateutil==2.6.0', 'simplejson==3.10.0',
         'Unidecode==0.4.20', 'feedwerk==1.0.0','raven==6.10.0'
     ])