Add two GitHub Actions workflows, that perform the following checks:
* Security scan the Python dependencies of the Dangerzone application
(`poetry.lock`), for the current/main branch.
* Build and security scan the Dangerzone container image for the
current/main branch.
* Security scan the Python dependencies of the Dangerzone application
(`poetry.lock`), for the latest release of Dangerzone (currently
v0.4.1).
* Download and security scan the Dangerzone container image for the
latest release of Dangerzone (currently v0.4.1).
The first two checks will run on branch pushes, PRs, and nightly. The
last two checks will run only nightly, since the code in the current
branch cannot affect already released artifacts.
Also, besides the security scans, these workflows will also update the
Security alerts in the GitHub page for the Dangerzone project, and print
the SARIF report to the stdout, for debugging purposes.
Closes#222
Adds tests for macOS and Windows with the dummy converter. Tests won't
actually perform the conversion. But it should be enough for us to test
the remainder of the codebase.
Fixes#229
