Update build_gesso.sh changing --force and --symbolic to -fs so it will work in docker.

build_gesso.sh

@@ -35,7 +35,7 @@ if [ -d "source" ]; then
   rm -rf source
   echo "Done removing old source directory ..."
 fi
-ln --force --symbolic "../source" source
+ln -fs "../source" source
 echo "Done symbolic linking source directory ..."
 
 echo "Removing style lint config and replacing with UW config ..."