I have a geopackage layer in QGIS which contains block outlines for parcels of land. They have been digitised with a gap between each block but the edges of adjacent polygons should actually share an edge. I'm looking for a way to calculate the midpoints of the gaps so I can drag the edges of the polygons to this point. Searching online I found that ArcGIS appears to have a tool that would help do this - midpoint, but I can't find a similar feature in QGIS. Can anyone suggest a method I could use?
[![enter image description here][1]][1] 


  [1]: https://i.sstatic.net/4Kmh6.png