Hi @gforghetti
The added data to the YAML file is not sufficient, as the new limit for uploads set as
RUN touch /usr/local/etc/php/conf.d/uploads.ini \
&& echo "upload_max_filesize = 10M;" >> /usr/local/etc/php/conf.d/uploads.ini
which you introduced above is not taking care of the /usr/local/etc/php/conf.d folder.
Note that I am not nitpicking here - my intent is to finish this discussion in a way that will provide the good solution for anyone who decides to use Docker to install wordpress.