Replace ujson with orjson

[valrus]

This PR is a small update to @rumpelsepp's here: #579
It just points the python-lsp-jsonrpc dependency at the branch I have PR'd at python-lsp/python-lsp-jsonrpc#29, to demonstrate the tests pass.

[ccordoba12]

It seems everything is here too, thanks @valrus and @rumpelsepp!

I'll release 1.12.0 first and then 2.0.0 a couple of weeks after that with this improvement.

[simon-liebehenschel]

@valrus @ccordoba12 Are there any existing tests to benchmark the python-lsp-server memory usage in the long run? The orjson library has some known "features" related to the memory usage and I really do not want to get OOM (Out of memory) errors or high memory usage after this pull request. I do not mean that this is guaranteed to get for python-lsp-server, but better to check to be sure.

[valrus]

@simon-liebehenschel I'm not aware of any tests covering memory usage, but I might take a stab at writing one. Can you provide any pointers to the issue(s) you're concerned about?

[simon-liebehenschel]

@simon-liebehenschel I'm not aware of any tests covering memory usage, but I might take a stab at writing one. Can you provide any pointers to the issue(s) you're concerned about?

https://github.com/ijl/orjson/issues/504

But I do not know if it will have any impact on python-lsp-server because depends on a specific usage. If you think this PR is safe, let's try it and see if anyone notices any regression in memory usage.