chore(docker): add custom APT source and install libssl3 for compatibility

Dockerfile

@@ -3,8 +3,11 @@ WORKDIR /var/www/html
 
 ENV COMPOSER_ALLOW_SUPERUSER=1
 
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends \
+COPY docker/apt/debian.sources /etc/apt/sources.list.d/debian.sources
+
+RUN apt-get -o Acquire::Check-Valid-Until=false update \
+    && apt-get install -y --allow-downgrades --no-install-recommends \
+        libssl3 \
         default-mysql-client \
         default-libmysqlclient-dev \
         libicu-dev \