Bump MSTest.TestAdapter from 1.3.2 to 2.1.2 in /src

Bumps [MSTest.TestAdapter](https://github.com/microsoft/testfx) from 1.3.2 to 2.1.2. - [Release notes](https://github.com/microsoft/testfx/releases) - [Commits](microsoft/testfx@v1.3.2...v2.1.2) Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/SvnManager.Tests/packages.config

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
- <package id="MSTest.TestAdapter" version="1.3.2" targetFramework="net47" />
+ <package id="MSTest.TestAdapter" version="2.1.2" targetFramework="net47" />
  <package id="MSTest.TestFramework" version="2.1.2" targetFramework="net47" />
 </packages>