Fix release~ .gitignore to allow .meta files at all directory levels

Author: jdetter

sdks/csharp/release~/.gitignore

@@ -1,11 +1,5 @@
-# Ignore most of NuGet package structure, except DLLs which are required by Unity.
-/*/*/*
+# Ignore DLLs - these will be populated by dotnet restore
+/*/*/*/*/*.dll
 
-!/*/*/analyzers
-!/*/*/analyzers.meta
-
-!/*/*/lib
-!/*/*/lib.meta
-
-# Ignore XML documentation metadata from packages too.
+# Ignore XML documentation
 *.xml