Beam Failure for Test on Windows

Currently when trying to run the GitHub action for tests on windows the BEAM pipeline is failing with:

```
...
--- FAIL: TestPipeline (2.09s)
testing.go:1231: TempDir RemoveAll cleanup: remove C:\Users\RUNNER~1\AppData\Local\Temp\TestPipeline1150232497\001\fhirBundleDir\bundle-0.json: The process cannot access the file because it is being used by another process.
...
```

This error is usually caused by failing to close the file after a `file.Open()`. However we did some preliminary investigations and haven't found an obvious cause.

Since this is only happening for the bundle-0.json the suspicion is that perhaps there could be a bug in the beam libraries. For now we are going to skip the BEAM tests for windows until this issue can be resolved and add a warning in the BEAM README.