fix(package.json): include Documentation directory with package

The Documentation directory should be included with the package so
the built package has the required documentation for users to refer
to when the package is installed.

Author: extendreality

package.json

@@ -35,6 +35,7 @@
         "*.meta",
         "*.asmdef",
         "*.xml",
+        "Documentation",
         "Runtime"
     ]
 }