Updating README with additional info

[andrekolodochka]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• I used npm run format for formatting the code before submitting the pull request.

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Added two items:

• It is possible to store non-sensitive data (such as connection URL, server names, etc) as configuration variables in GitHub. Unlike secrets, variables are visible and as result are easy to validate. I've updated the README with an example of how to define non-sensitive details (URL) as a variable.
• Some commands require a connection string, such as URL and token. The examples show how to define those in a workflow step. However, if those are defined on workflow step level, they cannot be used in subsequent steps (jf docker push for example). In this case these connection details need to be defined on either workflow or job level. I've added a clarification about that.

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[andrekolodochka]

I have read the CLA Document and I hereby sign the CLA

[andrekolodochka]

recheck

[github-actions]

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🐸 JFrog Frogbot

[eyalbe4]

@andrekolodochka,
Let us know if you'd like to continue promoting this PR.

[andrekolodochka]

@eyalbe4 I've created this PR four months ago and it hasn't been merged. since then there were other changes in the master so I need to resolve those conflicts now to make the PR mergeable again. I'm happy to resolve those if the PR will be merged. but if there's another four months of waiting and resolving yet another merge conflict - no, thanks. pls let me know if I should work on resolving the merge conflicts.

[eyalbe4]

Closing this PR for now.
We may get back to implementing the improvements suggested in this PR, as well as additional improvements in the future.