[unity] Add default asmdef files.

spine-unity/Assets/Spine/Editor/spine-unity-editor.asmdef

@@ -0,0 +1,10 @@
+{
+    "name": "spine-unity-editor",
+    "references": [
+        "spine-unity"
+    ],
+    "optionalUnityReferences": [],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false
+}

spine-unity/Assets/Spine/Editor/spine-unity-editor.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 173464ddf4cdb6640a4dfa8a9281ad69
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

spine-unity/Assets/Spine/Runtime/spine-unity.asmdef

@@ -0,0 +1,3 @@
+{
+	"name": "spine-unity"
+}

spine-unity/Assets/Spine/Runtime/spine-unity.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 68765d262e2128e4ab49c983f3411946
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: