fix mistake in docker image

1 job for 1-try-to-do-ci in 2 seconds (queued for 3 seconds)
Status Job ID Name Coverage
failed #10479


Name Stage Failure
compile Compile There is an unknown failure, please try again
Running with gitlab-ci-multi-runner 9.5.1 (96b34cc)
on Shared Docker CI runner (4cccac60)
Using Docker executor with image blang/latex-docker ...
Using docker image sha256:0f99cd0baee7bcd9207612a594bac383dc5609e8c625b296a27ce6261049e8f5 for predefined container...
Pulling docker image blang/latex-docker ...
ERROR: Job failed: Error response from daemon: pull access denied for blang/latex-docker, repository does not exist or may require 'docker login'