Update bug-report.yaml for 1.6-exp1 (#4463)

Author: duncanmacmichael

.github/ISSUE_TEMPLATE/bug-report.yaml

@@ -37,7 +37,7 @@ body:
       options:
         - "Windows App SDK 1.5.3: 1.5.240428000"
         - "Windows App SDK 1.5 Preview 1: 1.5.240205001-preview1"
-        - "Windows App SDK 1.5 Experimental 2: 1.5.240124002-experimental2"
+        - "Windows App SDK 1.6 Experimental 1: 1.6.240531000-experimental1"
   - type: dropdown
     attributes:
       label: Packaging type