[nano 33 iot] reintroduce debug.server.openocd.script to keep backward compatibility

this way using old cli version with an updated platform should work
if the cli is >= 0.35.0 and the platform is old it will work the old way

Author: umbynos

boards.txt

@@ -249,6 +249,7 @@ nano_33_iot.build.board=SAMD_NANO_33_IOT
 nano_33_iot.build.core=arduino
 nano_33_iot.build.extra_flags=-DCRYSTALLESS -D__SAMD21G18A__ {build.usb_flags}
 nano_33_iot.build.ldscript=linker_scripts/gcc/flash_with_bootloader.ld
+nano_33_iot.build.openocdoldscript=openocd_scripts/arduino_zero.cfg
 nano_33_iot.build.openocdscript=openocd_scripts/openocd.cfg
 nano_33_iot.build.variant=nano_33_iot
 nano_33_iot.build.vid=0x2341

platform.txt

@@ -138,6 +138,7 @@ debug.server=openocd
 debug.server.openocd.path={runtime.tools.openocd-0.10.0-arduino7.path}/bin/openocd
 debug.server.openocd.scripts_dir={runtime.tools.openocd-0.10.0-arduino7.path}/share/openocd/scripts/
 build.openocdinterface=interface/{programmer.protocol}.cfg
+debug.server.openocd.script={runtime.platform.path}/variants/{build.variant}/{build.openocdoldscript}
 debug.server.openocd.scripts.0={build.openocdinterface}
 debug.server.openocd.scripts.1={runtime.platform.path}/variants/{build.variant}/{build.openocdscript}
 debug.svd_file={build.svd_file}