Ensure the docker image has all public commits to build from

docker-build.sh

@@ -5,6 +5,7 @@ version=${1:-master}
 export PREFIX=/opt/gcc-arm-none-eabi-8-2018-q4-major/bin/
 
 cd /solo/targets/stm32l432
+git fetch
 git checkout ${version}
 version=$(git describe)
 make cbor