chore(developer): publishing vscode extension 🗼

[srl295]

For: #12758

Docs: https://code.visualstudio.com/api/working-with-extensions/publishing-extension

[srl295]

• Scoped names are not supported Support for scoped naming, e.g., @myscope/package-name? microsoft/vscode-vsce#186 (comment) - may need to rename the package to keyman-developer-vscode instead of @keymanapp/keyman-developer-vscode - perhaps with "private: true" to prevent accidental publish.

• Relative paths don't seem to work either

ERROR  invalid relative path: extension/../../../tsconfig.json

A bit more tricky. May need to break the linkage here, remove from the npm workspace, and depend on @keymanapp/… packages by version number.

Revisit that once it's actually working.