manually copy the logo to the www directory. Copying in Setup.hs doesn't work with the new Cabal

src/compiler/gf.cabal

@@ -16,6 +16,7 @@ tested-with: GHC==7.10.3, GHC==8.0.2, GHC==8.10.4, GHC==9.0.2
 data-files:
   www/*.html
   www/*.css
+  www/Logos/gf0.png
   www/P/*.png
   www/gfse/*.html
   www/gfse/*.css