Update .gitlab-ci.yml

2 jobs for master in 58 seconds (queued for 6 seconds)
Name Stage Failure
build-docker-master Build
Step 2/9 : RUN ip a
---> Using cache
---> 13c42931acea
Step 3/9 : RUN apk install git make gcc
---> Running in 61000e531e01
ERROR: 'install' is not an apk command. See 'apk --help'.
The command '/bin/sh -c apk install git make gcc' returned a non-zero code: 1
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1