ci(ossf): configured GitHub action and badge for OpenSSF scorecard

[VRamakrishna]

Going forward, tracking the health of a project using the OpenSSF Scorecard is going to be mandatory. For this purpose:

• I've configured a GitHub action to track OpenSSF criteria as per instructions in https://github.com/ossf/scorecard-action.
• I've also added a badge to the main README that reports the score inferred by the latest scan (triggered by each commit).

Pull Request Requirements

• Rebased onto upstream/main branch and squashed into single commit to help maintainers review it more efficient and to avoid spaghetti git commit graphs that obfuscate which commit did exactly what change, when and, why.
• Have git sign off at the end of commit message to avoid being marked red. You can add -s flag when using git commit command. You may refer to this link for more information.
• Follow the Commit Linting specification. You may refer to this link for more information.

Character Limit

• Pull Request Title and Commit Subject must not exceed 72 characters (including spaces and special characters).
• Commit Message per line must not exceed 80 characters (including spaces and special characters).

A Must Read for Beginners
For rebasing and squashing, here's a must read guide for beginners.

[tkuhrt]

LGTM (not that I have any voice)

[petermetz]

@VRamakrishna LGTM, thank you very much for adding this!

[petermetz]

LGTM (not that I have any voice)

@tkuhrt Yes you do! :-)