Modify GitLoaderContext to load any assembly in the folder

When the entry-point task is loaded in an AssemblyLoadContext (as it is
in MSBuild 16.5+ on .NET Core), the default ALC cannot load assemblies
from next to the task location, so assemblies that are redistributed with
the GitVersionTask package aren't automatically found. Extend the task's
private ALC to support loading any assembly from the task's folder.

Author: rainersigwald

src/GitVersionTask.MsBuild/LibGit2Sharp/GitLoaderContext.cs

@@ -11,18 +11,16 @@ namespace GitVersion.MSBuildTask.LibGit2Sharp
 {
     public sealed class GitLoaderContext : AssemblyLoadContext
     {
-        private readonly string[] assemblies;
         public static GitLoaderContext Instance { get; private set; }
 
-        private GitLoaderContext(string[] assemblies) => this.assemblies = assemblies;
-
-        public static void Init(params string[] assemblies) => Instance = new GitLoaderContext(assemblies);
+        public static void Init() => Instance = new GitLoaderContext();
 
         protected override Assembly Load(AssemblyName assemblyName)
         {
-            if (assemblies.Contains(assemblyName.Name))
+            var path = Path.Combine(Path.GetDirectoryName(typeof(GitLoaderContext).Assembly.Location), assemblyName.Name + ".dll");
+
+            if (File.Exists(path))
             {
-                var path = Path.Combine(Path.GetDirectoryName(typeof(GitLoaderContext).Assembly.Location), assemblyName.Name + ".dll");
                 return LoadFromAssemblyPath(path);
             }
 

src/GitVersionTask.MsBuild/TaskProxy.cs

@@ -18,7 +18,7 @@ static TaskProxy()
             try
             {
 #if !NETFRAMEWORK
-                GitLoaderContext.Init("GitVersionCore", "LibGit2Sharp");
+                GitLoaderContext.Init();
 #endif
                 LibGit2SharpLoader.LoadAssembly("GitVersionTask");