Bump MSTest.TestFramework from 3.6.3 to 3.7.0 in /docs/csharp/language-reference/operators/snippets/shared in the dotnet group across 1 directory

Bump MSTest.TestFramework from 3.6.3 to 3.7.0 in /docs/csharp/language-reference/operators/snippets/shared in the dotnet group across 1 directory #1421