No need for the sury packages

These were included in a misguided attempt to fix the nginx build process, which was failing due to OpenSSL not supporting parallel make jobs.

debian/buster/Dockerfile

@@ -6,19 +6,11 @@ LABEL version="1.0"
 RUN echo "deb http://security.debian.org/ buster/updates main" >> /etc/apt/sources.list
 
 RUN apt-get update \
-    && apt-get -yqqf --no-install-recommends install \
+    && apt-get -y --no-install-recommends install \
         apt-transport-https \
         lsb-release \
         ca-certificates \
         curl \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*
-
-RUN curl -ssL -o /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
-RUN echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list
-
-RUN apt-get update \
-    && apt-get -y --no-install-recommends install \
         git \
         dh-make \
         build-essential \

debian/jessie/Dockerfile

@@ -6,19 +6,11 @@ LABEL version="1.0"
 RUN echo "deb http://security.debian.org/ jessie/updates main" >> /etc/apt/sources.list
 
 RUN apt-get update \
-    && apt-get -yqqf --no-install-recommends install \
+    && apt-get -y --no-install-recommends install \
         apt-transport-https \
         lsb-release \
         ca-certificates \
         curl \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*
-
-RUN curl -ssL -o /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
-RUN echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list
-
-RUN apt-get update \
-    && apt-get -y --no-install-recommends install \
         git \
         dh-make \
         build-essential \

debian/stretch/Dockerfile

@@ -6,19 +6,11 @@ LABEL version="1.0"
 RUN echo "deb http://security.debian.org/ stretch/updates main" >> /etc/apt/sources.list
 
 RUN apt-get update \
-    && apt-get -yqqf --no-install-recommends install \
+    && apt-get -y --no-install-recommends install \
         apt-transport-https \
         lsb-release \
         ca-certificates \
         curl \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*
-
-RUN curl -ssL -o /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
-RUN echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list
-
-RUN apt-get update \
-    && apt-get -y --no-install-recommends install \
         git \
         dh-make \
         build-essential \