`--apikey` option in addition to setting a local environment variable

[chowsanthony]

cdisc-rules-engine/README.md

Line 320 in 39acfb4

### Updating the Cache (`update-cache`)

This section only mentions API key as an environment variable. The --apikey option also works. In fact, it takes precedent over the CDISC_LIBRARY_API_KEY variable when supplied.

Powershell command Get-ChildItem Env:CDISC_LIBRARY_API_KEY shows

Name                           Value
----                           -----
CDISC_LIBRARY_API_KEY          1c408c803a754ff2984879xxxxxxxxxx

Where, .\core.exe update-cache --apikey foobar yields

Exception: Request to https://api.library.cdisc.org/api/mdr/ct/packages returned unsuccessful 401 response
[PYI-25112:ERROR] Failed to execute script 'core' due to unhandled exception!