Updates for next runtime RC

[artursouza]

Update the SDK for the following breaking changes:

1. Service invocation now handles queryparams as string and not Map of string->string. Get the latest proto and fix any code in the SDK that refers to that.

2. When content type is "application/octet-stream", CloudEvent's data will now be in data_base64 and that should be exposed as byte[] to the application.

[wcs1only]

We discovered while working on this, we shouldn't actually need any changes to the python API for data_base64, however in the process, we discovered a runtime bug. Closing in favor of dapr/dapr#2794