gitlab-ci: do not regenerate the uroot container by default

1 job for master in 1 minute and 3 seconds
Status Job ID Name Coverage
failed #8223055


Name Stage Failure
tests Tests
2021/03/23 12:08:29 WARNING: You are not using one of the recommended Go versions (have = go1.16.2, recommended = [go1.13 go1.14]).
Some packages may not compile.
Go to to find out how to install a newer version of Go,
or use to install an additional version of Go.
2021/03/23 12:08:29 Filename is /tmp/initramfs.linux_amd64.cpio
2021/03/23 12:08:29 "" is neither package or path/glob: no required module provides package go.mod file not found in current directory or any parent directory; see 'go help modules'
make: *** [Makefile:39: out/initramfs.linux_amd64.cpio] Error 1
Cleaning up file based variables
ERROR: Job failed: exit code 2