docker: preserve environment variables

Signed-off-by: Josua Mayer <josua@solid-run.com>

docker/entry.sh

@@ -26,4 +26,4 @@ sudo -u build git config --global user.name "LX2160A Toolchain Container"
 sudo -u build git config --global user.email "support@solid-run.com"
 
 # now run the build script as the build user
-sudo -u build bash /work/runme.sh
+sudo -u build -E bash /work/runme.sh