ci: Added GH Code Scan action

[vicenteherrera]

This PR adds a GitHub Code Scan workflow to Git Hub actions for the repository, to look for vulnerabilities in the code and libraries used, with the following characteristics:

• It will scan the repository for vulnerabilities periodically (in case the vulnerability db updates with new ones), each Friday at 6:00 AM.
• It will trigger on push or pull requests to master
• It will scan go language files (autodetected supported programming language)
• It is non blocking, meaning that a detection will not block the pipeline
• Security alerts can be checked at: https://github.com/sysdiglabs/terraform-provider-sysdig/security/code-scanning

[tembleking]

LGTM, thanks @vicenteherrera!