Plugin pacman_pending_updates: switch to /bin/sh; update version

The plugin does not use any bash-specific features.  Thus it is not
necessary to depend on bash.

plugins/other/pacman_pending_updates

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 : <<=cut
 
@@ -25,7 +25,7 @@ This plugin will draw one line: the number of updates pending.
 
 =head1 VERSION
 
-  1.1.1
+  1.2.0
 
 =head1 AUTHOR