Update .gitlab-ci.yml - Images + Hello World

2 jobs for master in 6 seconds (queued for 1 second)
Name Stage Failure
failed
java Test
Checking out 38720d60 as master...
Removing build/

Skipping Git submodules setup
Executing "step_script" stage of the job script
$ javac src/*.java
/bin/sh: eval: line 96: javac: not found
Cleaning up file based variables
ERROR: Job failed: exit code 127
failed
python Test
Checking out 38720d60 as master...
Removing build/

Skipping Git submodules setup
Executing "step_script" stage of the job script
$ python src/hello.py $GREET > result.txt
/bin/sh: eval: line 96: python: not found
Cleaning up file based variables
ERROR: Job failed: exit code 127