Fix tar command for RHEL release

[szh]

Desired Outcome

Fix #405. Official docs must also be updated when this is released.

Implemented Changes

• Added the z option to the tar command for REHL release in CONTRIBUTING.md

Connected Issue/Story

Resolves #405

Changelog

• [x] The CHANGELOG has been updated, or
• [ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [ ] This PR includes new unit and integration tests to go with the code changes, or
• [x] The changes in this PR do not require tests

Documentation

• [x] Docs (e.g. READMEs) were updated in this PR
• [ ] A follow-up issue to update official docs has been filed here: [insert issue ID]()
• [ ] This PR does not require updating any documentation

Behavior

• [ ] This PR changes product behavior and has been reviewed by a PO, or
• [ ] These changes are part of a larger initiative that will be reviewed later, or
• [x] No behavior was changed with this PR

Security

• [ ] Security architect has reviewed the changes in this PR,
• [ ] These changes are part of a larger initiative with a separate security review, or
• [x] There are no security aspects to these changes

[shulifink]

@szh - when is RHEL going out? GA??

[szh]

@szh - when is RHEL going out? GA??

I'm unsure as to the status of this repo. Maybe we can set up a meeting with @jtuttle

[szh]

@szh - when is RHEL going out? GA??

I'm unsure as to the status of this repo. Maybe we can set up a meeting with @jtuttle

For the record, this CLI will be replacing the Ruby based CLI which has now been moved to cyberark/cyberark-conjur-cli-docker-based.