Almost all unit tests are failing

[Fasteroid]

200 out of the 203 total unit tests fail, probably all with this error:

Message: 
System.AggregateException : One or more errors occurred.
---- System.IO.FileNotFoundException : Could not load file or assembly 'Microsoft.CodeAnalysis.Workspaces, Version=4.9.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
---- The following constructor parameters did not have matching fixture data: RoslynFixture fixture

  Stack Trace: 
----- Inner Stack Trace #1 (System.IO.FileNotFoundException) -----
RoslynMetadataProviderStub.ctor(DTE dte)
RoslynFixture.ctor() line 13
----- Inner Stack Trace #2 (Xunit.Sdk.TestClassException) -----

Reproduce: Tests > Test Explorer then click the green play button

Things I tried:

• built Typewriter.Tests solution
• manually built every solution in the project
• tried upgrading the problematic dependency via nuget package manager (I couldn't get it to actually update)

Observations:

• Microsoft.CodeAnalysis.Workspaces 4.9.0.0 doesn't exist; the closest version (and the one that's installed at the time of writing) is 4.9.2

I have no idea what I'm doing, can I have some help? I want to PR a fix for #47 but I need to be able to run these unit tests first.

[AdaskoTheBeAsT]

I observed it from some version of code analysis - I will try to adress it but from strange reason files are locked