Update package manifest to point to local packages

TestProjects/ShaderGraph/Packages/manifest.json

 {
-	"dependencies": {
-	}
+    "dependencies": {
+        "com.unity.postprocessing": "file:../../../com.unity.postprocessing", 
+        "com.unity.render-pipelines.core": "file:../../../com.unity.render-pipelines.core", 
+        "com.unity.shadergraph": "file:../../../com.unity.shadergraph", 
+        "com.unity.render-pipelines.high-definition": "file:../../../com.unity.render-pipelines.high-definition", 
+        "com.unity.render-pipelines.lightweight": "file:../../../com.unity.render-pipelines.lightweight"
+    }, 
+    "testables": [
+        "com.unity.render-pipelines.shadergraph"
+    ]
 }