Patch .NET isolated DF templates

[davidmrdavid]

We've received recent reports that the DF templates for .NET isolated have stopped working out of the box. This PR makes 3 fixes to address the feedback:

1. Updates the DF isolated extension to version 1.1.1 (can I use a * pattern to have it always download the latest?)

2. Updates the Http extension to version 3.1.0 (was getting the following warning otherwise)

"""
Warning As Error: Detected package downgrade: Microsoft.Azure.Functions.Worker.Extensions.Http from 3.1.0 to 3.0.13. Reference the package directly from the project to select a different version.

FunctionApp2 -> Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore 1.2.0 -> Microsoft.Azure.Functions.Worker.Extensions.Http (>= 3.1.0)

FunctionApp2 -> Microsoft.Azure.Functions.Worker.Extensions.Http (>= 3.0.13)

"""

3. changes the use of CreateCheckStatusResponse to CreateCheckStatusResponseAsync which should address a runtime failure reading:

"""
Exception: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.
"""

[davidmrdavid]

I see the CI tests are failing to run, probably permissions-based. I think @soninaren has the permissions to run them?

[davidmrdavid]

@fabiocav - can we get an approval for this change? I see the tests aren't passing for what seems like a permission error. Usually I'd ping Naren to get those resolved (I think he has the right permissions) but I know he's OOF. Do you know how to get the CI passing?

[fabiocav]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[fabiocav]

@jviau had already approved, but I just fixed a pipeline issue that was causing the build to break. Once that is green, you should be good to merge.

[fabiocav]

Just went ahead and merged it

[javtec]

I was able to finally get the sample code to work from the instructions above. However, the instructions were not complete to solve the issue. @davidmrdavid you had mentioned to simply replace "CreateCheckStatusResponse" with "CreateCheckStatusResponseAsync".
But the final fix was to replace the whole line of code from this:

"return client.CreateCheckStatusResponse(req, instanceId);"

to this:

"return await client.CreateCheckStatusResponseAsync(req, instanceId);"

I added "await" and that got the code working.