Added mysql extension

Dockerfile

@@ -8,6 +8,7 @@ RUN apt -y update && apt -y install php-fpm \
     php7.3-curl \
     php7.3-mbstring \
     php7.3-sqlite3 \
+    php7.3-mysql \
     php7.3-xml \
     php7.3-zip \
     php7.3-redis \