Update .gitlab-ci.yml

1 job for master in 37 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
failed #55
alpine docker
build

00:00:37

 
Name Stage Failure
failed
build Build There is an unknown failure, please try again
	-d	Decompress
-t Test file integrity
-c Write to stdout
-f Force
-k Keep input files
make[1]: Leaving directory '/builds/ePirat/opusfile'
make[1]: *** [Makefile:853: dist-gzip] Error 1
make: *** [Makefile:887: dist] Error 2
ERROR: Job failed: exit code 2