ci: add M33 target

nucleo_l552ze_q tests building for M33 which is ARMV8_M_BASELINE.

nrf5340dk_nrf5340_cpuapp would also work, but it has a different name
(nrf5340pdk_nrf5340_cpuapp) in Zephyr 2.3, which makes it inconvenient.

.github/workflows/main.yml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         zephyr_version: [3.4.0, 2.7.3, 2.6.0, 2.5.0, 2.4.0, 2.3.0]
-        board: [qemu_x86, qemu_cortex_m3, qemu_cortex_r5, native_posix, qemu_riscv32, qemu_riscv64]
+        board: [qemu_x86, qemu_cortex_m3, qemu_cortex_r5, nucleo_l552ze_q, native_posix, qemu_riscv32, qemu_riscv64]
         test: [samples/rust-app, samples/no_std, samples/serial]
         exclude:
           - board: qemu_riscv32