Run CI against 4.2.1

Author: Gama11

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
   build:
     strategy:
       matrix:
-        haxe-version: ["3.4.7", "4.1.5", nightly]
+        haxe-version: ["3.4.7", stable, nightly]
         target: [html5, hl, neko, flash, cpp]
       fail-fast: false
     runs-on: ubuntu-latest