Update pyOCD to v0.31.0

Fix the FileProgrammer import path as that has changed.

Author: rwalton-arm

setup.py

@@ -84,6 +84,6 @@ def read(fname):
     install_requires=requirements,
     tests_require=test_requirements,
     extras_require={
-        "pyocd": ["pyocd==0.14.0"]
+        "pyocd": ["pyocd>=0.31.0"]
     },
 )

src/mbed_os_tools/test/host_tests_plugins/module_copy_pyocd.py

@@ -18,7 +18,7 @@
 
 try:
     from pyocd.core.helpers import ConnectHelper
-    from pyocd.flash.loader import FileProgrammer
+    from pyocd.flash.file_programmer import FileProgrammer
     PYOCD_PRESENT = True
 except ImportError:
     PYOCD_PRESENT = False