Upgrade MySQL dependency (refs #427)

.docker/web/Dockerfile

@@ -7,7 +7,7 @@ WORKDIR /code
 
 RUN pip install --upgrade pip
 
-ADD requirements.txt .
+ADD ../requirements.txt .
 RUN apt update \
     && apt install -y memcached libmemcached-dev \
     && pip install -r requirements.txt

docker-compose.server_ci.yml

@@ -7,7 +7,7 @@ version: '3'
 services:
 
   db:
-    image: mysql:5.5
+    image: mysql:8.0
     environment:
       - MYSQL_ROOT_PASSWORD=docker
       - MYSQL_DATABASE=ddcz

requirements.txt

@@ -1,5 +1,5 @@
 Django>=2.0.0,<2.1
-mysqlclient>=1.3.7,<1.4
+mysqlclient
 gunicorn
 sqlparse
 argon2-cffi