[App Service] az webapp list-runtimes: Pre-announce breaking changes (Azure#32905)

Author: seligj95

src/azure-cli/azure/cli/command_modules/appservice/_breaking_change.py

@@ -0,0 +1,23 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+
+from azure.cli.core.breaking_change import (register_output_breaking_change,
+                                            register_argument_deprecate)
+
+# az webapp list-runtimes output format change
+register_output_breaking_change(
+    'webapp list-runtimes',
+    description='The output will change from a flat list of strings to a structured list of objects '
+                'with keys: os, runtime, version, config, support, end_of_life.',
+    guide='Update scripts that parse the current string-list output. The new output is a list of '
+          'dicts with keys: os, runtime, version, config, support, end_of_life. '
+          'New --runtime and --support filter parameters will be added. '
+          'Use -o table for a human-readable view, or -o json and parse the new structured format.')
+
+# az webapp list-runtimes --linux removal
+register_argument_deprecate('webapp list-runtimes', '--linux', redirect='--os-type')
+
+# az webapp list-runtimes --show-runtime-details removal
+register_argument_deprecate('webapp list-runtimes', '--show-runtime-details')