The ornamental design for a packagingbox, as shown and described.
1. Packaging box
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Top
1.6 : Reference photo
The broken lines depict portions of the packaging box that form no part of the claimed design; the dash-dot broken lines define the bounds of the claimed design and form no part thereof; reproduction 1.1 is a front perspective view of the packaging box; reproduction 1.2 is a front view thereof; reproduction 1.3 is a back view thereof; reproduction 1.4 is a left view thereof where the right view is a mirror image; reproduction 1.5 is a top view thereof where the bottom view is a mirror image; reproduction 1.6 is a reference photo thereof showing an example of the usage of the subject design and forms no part of the claimed design.