GitHub Actions Updates: Redeploy Sandbox via Docker & Fix retry of Codecov upload

[tdonohue]

Follow-up to #2650

Description

This PR is just updates to our GitHub actions including:

1. Deploying to demo.dspace.org or sandbox.dspace.org after updates to our DockerHub images. (This used to be done via a webhook on DockerHub. But, moving it to GitHub actions so that we can have better control over when the re-deployment is called.)
2. Fixing a minor bug in the build.yml where the Codecov.io (code coverage) upload is not automatically retrying on failure. The issue seems to be that an upload failure doesn't throw an error by default, so we have to set fail_ci_if_error: true in the Codecov action to get the retry process to work properly.
3. Upgrading all action plugins to latest versions

Instructions for Reviewers

• No review is necessary. If these actions continue to work properly then this is a successful update.

[tdonohue]

This will need to be ported to dspace-7_x manually.

[tdonohue]

Ported to dspace-7_x in #2655