test: quarantine the two network-dependent integration tests as flaky

Both passed in the previous Windows run and failed in the next, with the endpoints
they depend on healthy throughout -- they fail on third-party availability, not on
anything in this repository.

#3014 calls api.github.com, which allows unauthenticated callers 60 requests an hour
per IP, shared across hosted runners; Paket takes its GitHub credentials from
paket.dependencies, so there is no token to hand it from CI. #1635 asserts on a
specific 401 from myget.org, so any hiccup produces a different message.

Flaky is the category this repository already keeps for exactly this, and it moves
them off the main job.

Author: fpellet

integrationtests/Paket.IntegrationTests/AddGithubSpecs.fs

@@ -11,6 +11,7 @@ open Paket
 open Paket.Domain
 
 [<Test>]
+[<Flaky>] // hits api.github.com, which rate-limits unauthenticated callers to 60 requests an hour per IP
 let ``#3014 paket github add clitool``() =
     let scenario = "i003014-add-github"
     use __ = prepare scenario

integrationtests/Paket.IntegrationTests/UpdatePackageSpecs.fs

@@ -139,6 +139,7 @@ let ``#1703 resolves locally``() =
     ignore __
 
 [<Test>]
+[<Flaky>] // asserts on a specific 401 from myget.org, so any network hiccup yields a different message
 let ``#1635 should tell about auth issue``() =
     try
         use __ = update "i001635-wrong-pw" |> fst