Upgrade packages to minimize the size of dependency graph

[sucrose0413]

Hi@qimingyuan, I found an issue in the Dropbox.Api.Integration.Tests.csproj:

Packages MSTest.TestAdapter v2.1.1, MSTest.TestFramework v2.1.1 and Microsoft.NET.Test.Sdk v16.7.1 transitively introduce 87 dependencies into project’s dependency graph (see dependency graph before upgrades), while MSTest.TestAdapter v2.2.1, MSTest.TestFramework v2.2.1 and Microsoft.NET.Test.Sdk v16.8.0 can only introduce 55 dependencies (see dependency graph after upgrades).

These upgrades can help project minimize the size of dependency graph.
Hope the PR can help you.

Best regards,
sucrose

[greg-db]

Thanks for putting this together! I'll ask the team to review this.

[sucrose0413]

Thanks a lot.@greg-db

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