Fix error in marshaling GitStatusOptions

Author: Molytho

LibGit2Sharp/Core/GitStatusOptions.cs

@@ -13,6 +13,8 @@ internal class GitStatusOptions : IDisposable
 
         public GitStrArrayManaged PathSpec;
 
+        public unsafe void* Baseline = (void*)0;
+
         public void Dispose()
         {
             PathSpec.Dispose();