workspaceFolderBasename is not expanded in config.

[teki]

Please describe the problem.
Trying to add this to command line arguments: "--compile-commands-dir=${workspaceFolder}/bazel-${workspaceFolderBasename}"

Logs
Expanded like this:

I[12:21:38.983] argv[8]: --compile-commands-dir=/my/workspace/bazel-${workspaceFolderBasename}

System information
clangd extension version: v0.1.9
Operating system: macOS 10.15.7

Note:
I can see the MS CPP extension used to have the same issue: microsoft/vscode-cpptools#2495

[HighCommander4]

There's a PR fixing this at #642