Improve OpenSSF Scorecard report

[mbrandenburger]

Currently, the FPC repo has a scorecard of 4.3 (see https://scorecard.dev/viewer/?uri=github.com/hyperledger/fabric-private-chaincode)

This issue is about improving our scorecard value by applying best practices as suggested by OpenSSF

TODOS:

• [x] Dangerous-Workflows
• [x] Token-Permissions #764
• [ ] Vulnerabilities #759
• [ ] Maintained
• [ ] Code-Review
• [ ] Binary-Artifacts
• [ ] Fuzzing (TBD)
• [ ] SAST
• [ ] Pinned-Dependencies
• [x] Security-Policy
• [ ] CII-Best-Practices
• [x] License
• [ ] Branch-Protection
• [ ] Packaging
• [ ] Signed-Releases