Make lt20 default; gate lt12 behind workflow input

Author: vectorrilke

.github/workflows/ci_windows_arm64_native.yaml

@@ -2,6 +2,12 @@ name: Build Windows ARM64 Native
 
 on:
   workflow_dispatch:
+    inputs:
+      build_lt12:
+        description: "Also build legacy libtorrent 1.2 (lt12)"
+        required: false
+        type: boolean
+        default: false
   push:
     branches:
       - main
@@ -23,19 +29,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include:
-          - libt_variant: lt12
-            libt_ref: c5ff6c3186a92ddec01f6f0a8146aaedb4a1c3f9
-            boost_version: "1.86.0"
-            libt_version_display: "1.2.20+gitc5ff6c3186"
-            archive_suffix: ""
-            artifact_name: arm64-native-lt12
-          - libt_variant: lt20
-            libt_ref: da7a68a440b7abf4eb1a237df7168be0b8b17084
-            boost_version: "1.91.0"
-            libt_version_display: "2.0.13+gitda7a68a440"
-            archive_suffix: "_lt20"
-            artifact_name: arm64-native-lt20
+        include: ${{ fromJson((github.event_name == 'workflow_dispatch' && inputs.build_lt12) && '[{"libt_variant":"lt12","libt_ref":"c5ff6c3186a92ddec01f6f0a8146aaedb4a1c3f9","boost_version":"1.86.0","libt_version_display":"1.2.20+gitc5ff6c3186","archive_suffix":"","artifact_name":"arm64-native-lt12"},{"libt_variant":"lt20","libt_ref":"da7a68a440b7abf4eb1a237df7168be0b8b17084","boost_version":"1.91.0","libt_version_display":"2.0.13+gitda7a68a440","archive_suffix":"_lt20","artifact_name":"arm64-native-lt20"}]' || '[{"libt_variant":"lt20","libt_ref":"da7a68a440b7abf4eb1a237df7168be0b8b17084","boost_version":"1.91.0","libt_version_display":"2.0.13+gitda7a68a440","archive_suffix":"_lt20","artifact_name":"arm64-native-lt20"}]') }}
     env:
       boost_root: "${{ github.workspace }}/../boost"
       libtorrent_root: "${{ github.workspace }}/../libtorrent-msvc-arm64"