Update to support VSCode 1.89.0

[psybers]

VSCode 1.89.0 now supports some of what this extension does:

Moving forward, it probably makes sense for users to use that feature. But this extension can still work! I view this extension as giving you work sets within a single SCM branch. So you could use the one built into VSCode to manage switching context when you switch branches, and then this extension ignores branch switches entirely.

Perhaps the list of contexts would be specific to each branch? So if I switch branches it would clear the list?

At any rate, the two features will fight each other so this extension needs updated.