release: update NEWS

NEWS

+======================================================
+network-manager-applet-1.8.4
+Overview of changes since network-manager-applet-1.8.2
+======================================================
+
+This is a new stable release of network-manager-applet.  Notable changes include:
+
+* nm-c-e: Major rework of the nm-connection-editor UI.
+* nm-c-e: Add support for MACsec.
+* nm-c-e: Add support for new PPPoE connections not limited to ethernet.
+* nm-c-e: Add support for bridge's group-forward-mask property.
+* applet: Fix nm-applet's status icon when a VPN has the default route.
+* applet: Always center dialogs on the screen.
+* libnma: Fix handling empty password for certificate chooser.
+* po: Updated Catalan, Croatian, Czech, Galician, Indonesian, Italian,
+  Kazakh, Lithuanian, Polish, Brazilian Portuguese, Punjabi, Romanian,
+  Serbian, Spanish translations.
+* Various bugfixes and minor improvements.
+
 ======================================================
 network-manager-applet-1.8.2
 Overview of changes since network-manager-applet-1.8.0