Bump Microsoft.NET.Test.Sdk from 16.8.3 to 16.9.4 (#95)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.3 to 16.9.4.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.8.3...v16.9.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/common.props

@@ -18,7 +18,7 @@
     <PostgresVersion>5.0.3</PostgresVersion>
     <NetStandardLibVersion>netstandard2.0</NetStandardLibVersion>
     <NetFrameworkVersion>net45</NetFrameworkVersion>
-    <TestSdkVersion>16.8.3</TestSdkVersion>
+    <TestSdkVersion>16.9.4</TestSdkVersion>
     <NetCoreTestVersion>netcoreapp3.1</NetCoreTestVersion>
     <NetFrameworkTestVersion>net471</NetFrameworkTestVersion>
   </PropertyGroup>