Remove libpng-config link unto itself

ubuntu/base/Dockerfile9

@@ -188,6 +188,7 @@ RUN uname -a \
         && python3 -c "from osgeo import gdal_array; print('SUCCESS')" \
         \
         && rm -r "${OTB_INSTALL_DIRNAME}/share/otb/swig/build" \
+        && rm -r "${OTB_INSTALL_DIRNAME}/bin/libpng-config" \
         \
         && echo 'PS1="${VIRTUAL_ENV_PROMPT}${PS1}"' >> "$HOME/.bashrc" \
         \