[godot] Add 4.2-stable to build matrix

.github/workflows/spine-godot-v4-all.yml

@@ -17,6 +17,8 @@ jobs:
             {"tag": "4.0.4-stable", "version": "4.0.4.stable", "mono": false},
             {"tag": "4.1.3-stable", "version": "4.1.3.stable", "mono": false},
             {"tag": "4.1.3-stable", "version": "4.1.3.stable", "mono": true},
+            {"tag": "4.2-stable", "version": "4.2.stable", "mono": false},
+            {"tag": "4.2-stable", "version": "4.2.stable", "mono": true},
           ]
     uses: ./.github/workflows/spine-godot-v4.yml
     with: