When initializing repository on 5.5.2f1 (x86), I get:

Failed to load 'Assets/Editor/GitHub/sfw.dll', expected x86 architecture, but was x64 architecture. You must recompile your plugin for x86 architecture.
GitHub.Unity.RepositoryWatcher:Initialize() (at /Users/stanleygoldman/Documents/UnityInternal/src/GitHub.Api/Events/RepositoryWatcher.cs:70)
GitHub.Unity.RepositoryWatcher:Initialize() (at /Users/stanleygoldman/Documents/UnityInternal/src/GitHub.Api/Events/RepositoryWatcher.cs:69)
GitHub.Unity.RepositoryManager:Initialize() (at /Users/stanleygoldman/Documents/UnityInternal/src/GitHub.Api/RepositoryManager.cs:178)
GitHub.Unity.c__async0:MoveNext() (at /Users/stanleygoldman/Documents/UnityInternal/src/GitHub.Api/ApplicationManagerBase.cs:97)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(c__async0&)
GitHub.Unity.ApplicationManagerBase:RestartRepository()
GitHub.Unity.ApplicationManager:RestartRepository() (at /Users/stanleygoldman/Documents/UnityInternal/src/UnityExtension/Assets/Editor/GitHub.Unity/ApplicationManager.cs:91)
GitHub.Unity.c__AnonStorey0:<>m__4(Task`1) (at /Users/stanleygoldman/Documents/UnityInternal/src/GitHub.Api/RepositoryLocator.cs:83)
System.Threading.Tasks.ThreadPoolTaskScheduler:TaskExecuteWaitCallback(Object)

I know, it's weird that I even use x86 version today, but it's a long story involving some legacy x86 dlls I was already using, so I can't easily switch to x64 right now.

Version of Unity: 5.5.2f1 (x86)
Version of GitHub for Unity: 0.8.0.0
Platform: Win7