Remove unneeded dependencies from shared library

[Brandon Waterloo [MSFT]]

Currently the shared library has just vscode-jsonrpc and dayjs as dependencies. Neither are particularly large but removing them could be helpful.

As far as I can tell, vscode-jsonrpc is only used to supply CancellationToken.None. It also is used for typings, but can be made a dev dependency.

For dayjs, we could potentially implement our own parsing, and leave the responsibility of formatting human-readable dates to the library's caller.

• vscode-jsonrpc
• dayjs

[Brandon Waterloo [MSFT]]

dayjs is so small and so optimized it's not worth bothering to take the time to remove it.