sway: fix volume keys for dynamic pa sink

bin/volume

@@ -0,0 +1,23 @@
+#!/bin/bash
+sink=$(pactl list sinks | grep -B 1 "State: RUNNING" | grep -oE '[0-9]*')
+cmd=""
+
+if [ -z "$sink" ]; then
+  echo "ERROR: invalid sink: \"$sink\""
+  exit 1
+fi
+
+case $1 in
+  d*)
+    pactl set-sink-volume $sink -5%
+    ;;
+  i*)
+    pactl set-sink-volume $sink +5%
+    ;;
+  m*)
+    pactl set-sink-mute $sink toggle
+    ;;
+  *)
+    echo "ERROR: invalid command: \"$1\""
+    ;;
+esac