Fix README.md

[sinsukehlab]

Change the docker package to pull in Step 4

Why:

Closes #6

What's being changed:

I have changed some instructions in Step 4 so that learners can pull the correct Docker image. :warning: Some screenshots need changing.

Check off the following:

• [x] For workflow changes, I have verified the Actions workflows function as expected.
• [x] For content changes, I have reviewed the style guide.

[sinsukehlab]

@heiskr @dihydroJenoxide I would appreciate it if you could review this PR at your earliest convenience. Replacing those screenshots that I indicated would be an arduous task, but I would be very grateful if you could improve this PR.

[sinsukehlab]

I would like to open another PR to close #8 after this PR is merged.

[wongcyrus]

The instruction should ask user to get the SHA tag from GitHub Action for Activity: Pull your image

Here is video demo for the step. Demo to get the tag from GitHub Action

[sinsukehlab]

The instruction should ask user to get the SHA tag from GitHub Action for Activity: Pull your image

Here is video demo for the step. Demo to get the tag from GitHub Action

You can get the tag from the Packages heading link. It redirects to the list of packages you have published.

[sinsukehlab]

@chadfawcett I highly appreciate your suggestions. I have committed some suggestions. I have also cherry-picked a commit from another branch.

[sinsukehlab]

I have split this PR. PR #19 changes the YAML code block.

[heiskr]

This looks like a useful set of changes, I'll go ahead and merge but feel free to open additional pull requests.