Add Zephyr build to Github actions

.github/workflows/test.yml

@@ -118,8 +118,10 @@ jobs:
             path: nxp/nxp-twrkv58f220m-lwip-freertos
           - name: infineon-xmc4700_4800-lwip-rtx-rtos
             path: infineon/infineon-xmc4700_4800-lwip-rtx-rtos
+          - name: zephyr
+            path: zephyr
     name: ${{ matrix.example.name }}
     steps:
       - uses: actions/checkout@v3
       - name: ${{ matrix.example.name }}
-        run: make -C examples/${{ matrix.example.path }} build
+        run: make -C examples/${{ matrix.example.path }} build