disable interactive frontend for apt in docker builds

.github/workflows/tools.yml

@@ -61,13 +61,13 @@ jobs:
           [[ "${{ matrix.release }}" == "bionic" ]] && \
           cat <<EOF >> Dockerfile
           RUN apt-get update && \
-              apt-get install -y software-properties-common && \
+              DEBIAN_FRONTEND=noninteractive apt-get install -y software-properties-common && \
               add-apt-repository -y ppa:libretime/libretime
           EOF
 
           cat <<EOF >> Dockerfile
           RUN apt-get update && \
-              apt-get -y install \
+              DEBIAN_FRONTEND=noninteractive apt-get -y install \
               python3 \
               python3-pip \
               $(cat packages.list)