Add 2.12.x to build matrix.

Author: SimY4

.github/workflows/build-and-test.yml

@@ -17,7 +17,7 @@ jobs:
 
     strategy:
       matrix:
-        scala: [2.13.x, 3.3.x]
+        scala: [2.12.x, 2.13.x, 3.3.x]
 
     steps:
       - uses: actions/checkout@v6