Update CHANGELOG

CHANGELOG.md

@@ -4,6 +4,8 @@ FEATURES:
 
   - **New Command: `vagrant powershell`**: For machines that support it,
     this will open a PowerShell prompt.
+  - **New Command: `vagrant port`**: For machines that support it, this will
+    display the list of forwarded ports from the guest to the host.
   - **Linked Clones**: VirtualBox and VMware providers now support
     linked clones for very fast (millisecond) imports on up. [GH-4484]
   - **Snapshots**: The `vagrant snapshot` command can be used to checkpoint