Update bug-report.yaml for 1.5.6 and 1.6-preview1 (#4637)

.github/ISSUE_TEMPLATE/bug-report.yaml

@@ -35,8 +35,8 @@ body:
       label: NuGet package version
       description: Specify the version of Windows App SDK (or Project Reunion) you're using.
       options:
-        - "Windows App SDK 1.5.5: 1.5.240627000"
-        - "Windows App SDK 1.5 Preview 1: 1.5.240205001-preview1"
+        - "Windows App SDK 1.5.6: 1.5.240802000"
+        - "Windows App SDK 1.6 Preview 1: 1.6.240807006-preview1"
         - "Windows App SDK 1.6 Experimental 2: 1.6.240701003-experimental2"
   - type: dropdown
     attributes: