Handle connection problems gracefully

[britter]

We're using minIO provided by https://hetzner.com and unfortunately it's not super reliable. Every once in a while we have builds failing with:

 * What went wrong:
org.gradle.internal.operations.BuildOperationInvocationException (no error message)
> io.minio.errors.ErrorResponseException (no error message)

I'm not exactly sure where this is happening in the plugin, but I think the plugin should handle this gracefully and fall back to executing without build cache.

[britter]

Another variant of this problem:

Error connecting to build cache object store fsn1.your-objectstorage.com
io.minio.errors.ServerException: server failed with HTTP status code 504
	at io.minio.S3Base$1.onResponse(S3Base.java:767)
	at io.minio.S3Base$1.onResponse(S3Base.java:625)
	at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:576)
FAILURE: Build failed with an exception.