Added v0.8.3 changelog

CHANGELOG.md

+## 0.8.3 (Aug 8, 2015)
+
+FEATURES:
+
+  * **[Beta] Artifice post-processor:** Override packer artifacts during post-
+      processing. This allows you to **extract artifacts from a packer builder**
+      and use them with other post-processors like compress, docker, and Atlas.
+
+IMPROVEMENTS:
+
+  * Many docs have been updated and corrected; big thanks to our contributors!
+  * builder/openstack: Add debug logging for IP addresses used for SSH [GH-2513]
+  * builder/openstack: Add option to use existing SSH keypair [GH-2512]
+  * builder/openstack: Add support for Glance metadata [GH-2434]
+  * builder/qemu and builder/vmware: Packer's VNC connection no longer asks for
+      an exclusive connection [GH-2522]
+  * provisioner/salt-masterless: Can now customize salt remote directories [GH-2519]
+
+BUG FIXES:
+
+  * builder/openstack: track new IP address discovered during RackConnect [GH-2514]
+  * post-processor/atlas: atlas_url configuration option works now [GH-2478]
+  * post-processor/compress: Now supports interpolation in output config [GH-2414]
+  * provisioner/powershell: Elevated runs now receive environment variables [GH-2378]
+  * provisioner/salt-masterless: Clarify error messages when we can't create or
+      write to the temp directory [GH-2518]
+  * provisioner/salt-masterless: Copy state even if /srv/salt exists already [GH-1699]
+  * provisioner/salt-masterless: Make sure /etc/salt exists before writing to it [GH-2520]
+
 ## 0.8.2 (July 17, 2015)
 
 IMPROVEMENTS: