plain text request rejected by `Content type error`

[98sean98]

Plain text requests are now being rejected by Content type error, and the inference function wrapped by @app.predict simply doesn't get executed.

For example, sending a curl request:

curl -X POST http://localhost:4000/predict -H 'Content-Type: text/plain' -d 'hello world'

returns

Content type error

But

curl -X POST http://localhost:4000/predict -H 'Content-Type: application/json' -d '{}'

executes the inference function with an expected output.

This is without any change to the inference function.

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This problem only surfaced in version 0.1.0 but not 0.0.5.