Add a security policy

[CAM-Gerlach]

Add a standard security policy based on that for the Spyder organization

[CAM-Gerlach]

Seems something went wrong with one of the typing dependencies?

INFO: pip is looking at multiple versions of python-lsp-black[dev] to determine which version is compatible with other requirements. This could take a while.
ERROR: Ignored the following yanked versions: 0.1.0, 0.1.1, 0.1.2, 0.1.3
ERROR: Could not find a version that satisfies the requirement types-pkg_resources; extra == "dev" (from python-lsp-black[dev]) (from versions: none)
ERROR: No matching distribution found for types-pkg_resources; extra == "dev"

I can ci skip this but I wanted to give you a chance to look at the CI output first.