Workflows: enable f1_dual_rev1 board

Other f1 boards are legacy and disabled

Author: dron0gus

.github/workflows/build-firmware.yaml

@@ -15,7 +15,7 @@ jobs:
           # - build-target: f1_rev2
           # - build-target: f1_rev3
           # - build-target: f1_dual
-          # - build-target: f1_dual_rev1
+          - build-target: f1_dual_rev1
 
     steps:
       - uses: actions/checkout@v1