ci: nightly db build - pin download artifact action to v3

Author: NGPixel

.github/workflows/dev-db-nightly.yml

@@ -148,7 +148,7 @@ jobs:
         ref: 'feat/postgres'
 
     - name: Download DB Dump
-      uses: actions/download-artifact@v3.0.0
+      uses: actions/download-artifact@v3
       with:
         name: dump