Dockerfile: Create a non-root user "build"
Dockerfile: Create a non-root user "build"

Fix issue https://github.com/gmacario/easy-build/issues/211

Signed-off-by: Gianpaolo Macario <d50c09b51e61901a1c5054dce86f92776c198faa@mentor.com>
gmacario/easy-build