[GRDM-48126] Add support for httpx>=0.28.0

[yacchin1205]

Creating folders becomes creating empty files when used with httpx >= 0.28.0 due to the following changes to httpx.

encode/httpx#3364

When creating a folder, rdmclient uses the new_folder URL passed from WaterButler. This contains the kind=folder parameter, and the folder is created by passing name=folder name in addition to this parameter.
This is a behavior that expects httpx to combine the query parameters given in the url argument with the query parameters given in params, but the above pull request has changed it to use only params.

This pull request will add support for the new behavior of httpx.

Note that this problem can be temporarily avoided by downgrading httpx.

pip install httpx==0.27.0