CI: bump setup-dlang to v2

Signed-off-by: Andrei Horodniceanu <a.horodniceanu@proton.me>

.github/workflows/d.yml

@@ -20,15 +20,15 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - uses: dlang-community/setup-dlang@4c99aa991ce7d19dd3064de0a4f2f6b2f152e2d7
+    - uses: dlang-community/setup-dlang@v2
 
     - name: 'Build & Test'
       run: |
         # Build the project, with its main file included, without unittests
-        dub build --compiler=$DC
+        dub build
         # Build and run tests, as defined by `unittest` configuration
         # In this mode, `mainSourceFile` is excluded and `version (unittest)` are included
         # See https://dub.pm/package-format-json.html#configurations
-        dub test --compiler=$DC
+        dub test
         # Run tests
         cd tests && rdmd test