Task/modify installation manual (#303)

* updated installation.md

* temporarily deleted the metal urp test for unity 2023.1 because 2023.1/staging is broken.

Author: H3idi-X

.yamato/osx_metal-urp-2023.1.yml

@@ -10,4 +10,4 @@ Installing the package requires the following steps.
 1. Click the **+** button, and choose **Add package from git URL** 
 1. Type in `com.unity.toonshader` and click the **Add** button. 
 
-We can also specify a particular version, for example: `com.unity.toonshader@0.8.4-preview`
+We can also specify a particular version, for example: `com.unity.toonshader@0.9.2-preview`