Update Jenkinsfile to fix push to RubyGems

[john-odonnell]

Desired Outcome

Jenkins build fails when publishing the CLI to RubyGems.org.

Currently fails with:

[2022-05-31T18:38:28.294Z] fatal: unsafe repository ('/src' is owned by someone else)
[2022-05-31T18:38:28.294Z] To add an exception for this directory, call:
[2022-05-31T18:38:28.294Z]
[2022-05-31T18:38:28.294Z] git config --global --add safe.directory /src

when running:

sh 'docker run -i --rm -v $PWD:/src -w /src alpine/git clean -fxd' in the Jenkinsfile.

Implemented Changes

Instead of running git commands from an alpine/git container, I've moved the commands to run directly in the shell.

If we still want to use an alpine/git container, we can run something like this, but it probably isn't necessary:

sh '''
  docker run -i --rm \
    --entrypoint /bin/sh \
    -v $PWD:/src -w /src \
    alpine/git -c '
      git config --global --add safe.directory /src
      git clean -fxd
    '
'''

Connected Issue/Story

CyberArk internal issue link: ONYX-21426

Definition of Done

At least 1 todo must be completed in the sections below for the PR to be
merged.

Changelog

• 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
• The changes in this PR do not require tests

Documentation

• 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
• 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
• There are no security aspects to these changes

[rpothier]

LGTM!