json: cannot unmarshal bool into Go value of type string

So this might be a problem in the OpenAPI, but the error is quite long. Perhaps someone has some insight.

Reproducer:
```
git clone https://github.com/jdegre/5GC_APIs
# commit da92f21c0e6b2b112f79670eb61cf9f7617bba22 as of right now
cd 5GC_APIs
apisprout TS32291_Nchf_ConvergedCharging.yaml
```
gives the attached long error, ending with:
```
Error while unmarshalling property 'required' (*[]string): json: cannot unmarshal bool into Go value of type string
```
[apisprout.log](https://github.com/danielgtaylor/apisprout/files/12747487/apisprout.log)

Start by reproducing the command shown in the issue against TS32291_Nchf_ConvergedCharging.yaml at commit da92f21c0e6b2b112f79670eb61cf9f7617bba22, then read the attached apisprout.log from the reported unmarshalling error backward. Compare the `required` value in the OpenAPI document with the type expected by the loader. Done means the reproducer has a clear, verified outcome without the reported failure or an explicitly actionable incompatibility message.

Written by the indexing model from the issue text.