Fix package version

[pablochacin]

Description

Separates the disruptor version to build from the release version to better handle different use cases such as publishing the latest development version or publishing a release.

Fixes #268

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works.
• I have run linter locally (make lint) and all checks pass.
• I have run tests locally (make test) and all tests pass.
• I have run relevant e2e test locally (make e2e-xxx for agent, disruptors, kubernetes or cluster related changes)
• Any dependent changes have been merged and published in downstream modules
  

[roobre]

Looking great, the split into three makes the thing very easy to read.

Left a few nits suggesting moving away from double negations (! -z).