Add apt_upgrade rule (#761)

* apt_list_upgradable: Prepend sudo to suggestion if used in command

* Add apt_upgrade rule

This suggests `apt upgrade` after `apt list --upgradable` if there are
packages to upgrade. It pairs well with the `apt_list_upgradable` rule,
which suggests `apt list --upgradable` after `apt update` if there are
packages to upgrade.

* Add apt_upgrade rule to README

thefuck/rules/apt_list_upgradable.py

@@ -11,5 +11,6 @@ def match(command):
     return "Run 'apt list --upgradable' to see them." in command.output
 
 
+@sudo_support
 def get_new_command(command):
     return 'apt list --upgradable'

thefuck/rules/apt_upgrade.py

@@ -0,0 +1,16 @@
+from thefuck.specific.apt import apt_available
+from thefuck.specific.sudo import sudo_support
+from thefuck.utils import for_app
+
+enabled_by_default = apt_available
+
+
+@sudo_support
+@for_app('apt')
+def match(command):
+    return command.script == "apt list --upgradable" and len(command.output.strip().split('\n')) > 1
+
+
+@sudo_support
+def get_new_command(command):
+    return 'apt upgrade'