.gitlab-ci.yml: Fix a typo in a variable name

4 jobs for valentindavid/variable_typo in 59 minutes and 35 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build
passed #258240519
aarch64
aarch64

00:31:55

passed #258163182
x86_64
amd64

00:14:25

passed #258163184
ppc64le
ppc64le

00:15:25

failed #258163183
aarch64
aarch64

00:09:42