Enable again the unit tests

.github/workflows/ci.yml

@@ -42,6 +42,5 @@ jobs:
         uses: goto-bus-stop/setup-zig@v2
         with:
           version: master
-# Temporarily disabled.
-#      - name: Run unit tests
-#        run: zig build test
+      - name: Run unit tests
+        run: zig build test