buildx failed with: ERROR: failed to solve: process "/bin/sh -c curl https://ftp.rtems.org/pub/rtems/releases/${RTEMS_MAJOR}/rc/${RTEMS_VERSION}/sources/rtems-source-builder-${RTEMS_VERSION}.tar.xz | tar -xJ && mv rtems-source-builder-${RTEMS_VERSION} rsb" did not complete successfully: exit code: 2