Adding OneBranch pipeline YAML config file for OSS_Microsoft_PSSA-Official

[adityapatwardhan]

PR Summary

Onboarding to OneBranch pipelines

PR Checklist

• [ ] PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• [ ] Summarized changes
• [ ] Change is not breaking
• [ ] Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• [ ] Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• [ ] This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.

[TravisEz13]

Signing needs to be improved, but I'll open a second PR to do that and fix some fit and finish.