Updated requirements for python 3.8 support

updated:
channels to 2.3.1
channels-redis to 2.4.1
daphne to 2.4.0

Added python 3.8 test for travis

.travis.yml

@@ -98,6 +98,17 @@ matrix:
         - mypy openslides/ tests/
         - pytest --cov --cov-fail-under=73
 
+    - name: "Server: Tests Python 3.8"
+      language: python
+      python:
+        - "3.8"
+      script:
+        - flake8 openslides tests
+        - isort --check-only --diff --recursive openslides tests
+        - black --check --diff --target-version py36 openslides tests
+        - mypy openslides/ tests/
+        - pytest --cov --cov-fail-under=73
+
     - name: "Client: Linting"
       language: node_js
       node_js: "10.9"

requirements/big_mode.txt

@@ -1,5 +1,5 @@
 # Requirements for Redis and PostgreSQL support
-channels-redis>=2.2,<2.4
+channels-redis>=2.2,<2.5
 django-redis-sessions>=0.6.1,<0.7
 psycopg2-binary>=2.7.3.2,<2.9
 aioredis>=1.1.0,<1.3

requirements/production.txt

@@ -3,8 +3,8 @@ autobahn==19.5.1
 
 # Requirements for OpenSlides in production in alphabetical order
 bleach>=1.5.0,<3.2
-channels>=2.1.2,<2.2
+channels>=2.1.2,<2.4
-daphne>=2.2,<2.3
+daphne>=2.2,<2.5
 Django>=2.1,<2.3
 djangorestframework>=3.9.4,<3.10
 jsonfield2>=3.0,<3.1