upgrade ttrss to latest

Dockerfile

@@ -1,4 +1,4 @@
-FROM nginx:1.17.3-alpine
+FROM nginx:1.17.8-alpine
 
 RUN \
   apk add --no-cache \
@@ -21,23 +21,24 @@ RUN \
     php7-mbstring \
     php7-json \
     php7-fileinfo \
+    git \
     tar
 
 EXPOSE 80 443
 
+RUN \
+    git clone https://git.tt-rss.org/fox/tt-rss.git /var/lib/tt-rss && \
+    cd /var/lib/tt-rss && \
+    git checkout 076c5382fafcaf5ffd2bd41752e8e3c3b20e6af0
+
 WORKDIR /app
 COPY CHECKS /app/CHECKS
 
-ADD https://git.tt-rss.org/fox/tt-rss/archive/19.8.tar.gz /tmp/ttrss.tar.gz
-
 COPY nginx.conf /etc/nginx/conf.d/default.conf
 COPY php-fpm.conf /etc/php7/php-fpm.d/ttrss.conf
 COPY install-db.php /var/lib/tt-rss-install/install-db.php
 COPY supervisor.conf /var/lib/tt-rss-install/supervisor.conf
 COPY manage-supervisord.py /var/lib/tt-rss-install/manage-supervisord.py
-
-RUN tar -xzf /tmp/ttrss.tar.gz -C /var/lib
-
 COPY config.php /var/lib/tt-rss/config.php
 
 RUN \