bullseye upgrade: pause to process df -h output

howto/upgrades/bullseye.md

@@ -100,6 +100,7 @@ connection.
         apt update &&
         ( apt -o APT::Get::Trivial-Only=true dist-upgrade || true ) &&
         df -h &&
+        read -n1 -s -r -p "Press any key to continue, Ctrl-C to abort." &&
         apt -y -d full-upgrade &&
         apt -y -d upgrade &&
         apt -y -d dist-upgrade &&