there probably are filters that do this,
not sure if any of the native ones do, however.
you could have a look in the distort section of the filters,
BUT
this is very easy to do either in the motion tab or by manipulating the wireframe
1. double click a clip int the viewer,
go to the motion tab,
under Distort, adjust Aspect ratio,
and then adjust Scale accordingly
2.in the canvas, turn on image & wireframe
select the clip in the timeline,
grab the wireframe in the canvas with your mouse,
hold SHIFT, and drag.
you'll probable have to zoom the canvas out a bit so you've got room to move.
nick