According to this answer, it seems that we need to add some https sources. So, add support for https apt sources by installing a couple of packages:[...]
E: The method driver /usr/lib/apt/methods/https could not be found.The command '/bin/sh -c apt-get update && apt-get clean ### Sonar version 5.6 - timestamp' returned a non-zero code: 100
apt-get install apt-transport-https ca-certificates
This can be done by modifying the file Dockerfile, located in the folder docker-sonarqubeLook for:
RUN apt-get install -y --force-yes sonar=5.6
replace it with the following:
RUN apt-get install apt-transport-https ca-certificates -y --force-yes sonar=5.6
David E. Fonseca