[FR]: Add OpenSSF Scorecard Badge for Security Insights

### Does the feature exist in the most recent commit?

changes currently available in fork: https://github.com/kiselik/googletest/tree/ossf
PR will be raised a little bit later

### Why do we need this feature?

I’d like to suggest adding the [OpenSSF Scorecard](https://github.com/ossf/scorecard) badge to this repository’s README to improve transparency around security best practices.

The Scorecard project is an initiative from the Open Source Security Foundation (OpenSSF) that evaluates open-source repositories against a set of automated security checks (e.g., branch protection, dependencies, fuzzing, CI/CD usage, etc.).

#### Benefits

- Shows commitment to open-source security
- Increases trust with users and contributors
- Automatically updates with your project’s latest Scorecard rating

### Describe the proposal.

the proposed changes are implemented via 2 steps:
- setting up gitHub workflow with weekly scheduled job
- publishing results as a badge which is available via README

### Is the feature specific to an operating system, compiler, or build system version?

this feature doesn't require specific operating system, compiler, or build system version

Review the changes in the linked ossf fork first, then inspect the repository README and GitHub workflow configuration. Confirm that the workflow runs weekly and publishes the OpenSSF Scorecard result as a README badge; no specific test is mentioned in the issue.

Written by the indexing model from the issue text.