Update CI_API_TOKEN to CI_JOB_TOKEN

What does this MR do and why?

This changes the usage of our custom set CI_API_TOKEN to the pre-defined CI_JOB_TOKEN. CI_JOB_TOKEN is valid only while the job is running. After the job finishes, the token access is revoked and you cannot use the token anymore. This is more secure than using a TOKEN that is valid for a longer period.

How to set up and validate locally

Once merged, it should run the build:python:env and build:ruby:env jobs correctly.

Related to #109 (closed)