[clangd-vscode] Update VScode dependencies

Summary:
This allows the extension to work with LSP 3.0 and is useful for testing.

Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>

Reviewers: ilya-biryukov

Subscribers: hokein, klimek, ilya-biryukov, jkorous-apple, ioeric, MaskRay, cfe-commits

Differential Revision: https://reviews.llvm.org/D45285

llvm-svn: 329574