fix(deployment): raises exception when package depends not found

This commit fixes the issue where unhelpful error message is displayed
when a package depends referenced in a deployment manifest is not
found.

Wrike Ticket: https://www.wrike.com/open.htm?id=1237582859

riocli/deployment/model.py

@@ -53,11 +53,16 @@ def find_object(self, client: Client) -> typing.Any:
         return obj if guid else False
 
     def create_object(self, client: Client, **kwargs) -> typing.Any:
-        pkg_guid, pkg = self.rc.find_depends(self.metadata.depends,
-                                             self.metadata.depends.version)
+        pkg_guid, pkg = self.rc.find_depends(
+            self.metadata.depends,
+            self.metadata.depends.version)
 
         if pkg_guid:
             pkg = client.get_package(pkg_guid)
+
+        if not pkg:
+            raise ValueError('package not found: {}'.format(self.metadata.depends))
+
         pkg.update()
 
         default_plan = pkg['plans'][0]