added zlinq

Packages/ZLinq.Unity/package.json

@@ -0,0 +1,11 @@
+{
+    "name": "com.cysharp.zlinq",
+    "displayName": "ZLinq",
+    "author": { "name": "Cysharp, Inc.", "url": "https://cysharp.co.jp/en/" },
+    "version": "1.5.5",
+    "unity": "2021.3",
+    "description": "Zero allocation LINQ with Span and LINQ to SIMD, LINQ to Tree(FileSystem, GameObject, etc...) for all .NET platforms and Unity.",
+    "keywords": [ "LINQ" ],
+    "license": "MIT",
+    "category": "Scripting"
+}