Checks version of pip

Checks the latest version of pip is installed before checking the dependencies

Change-Id: I2dff11d8e1b313a09db616170a0791716403f735
Signed-off-by: Matthew Dalzell <matthew.dalzell@arm.com>
diff --git a/build_helper/build_helper_configs.py b/build_helper/build_helper_configs.py
index d14669c..c19d900 100755
--- a/build_helper/build_helper_configs.py
+++ b/build_helper/build_helper_configs.py
@@ -142,6 +142,7 @@
                                           "image_signing/scripts/tfm_ns_signed.bin ;"
                                           "popd"),
                    "nxp/lpcxpresso55s69": ("echo 'LPCXpresso55S69 board post process\n'; "
+                                           "python3 -m pip install --upgrade pip; "
                                            "pip3 install libusb; "   # this should not go here, remove after test
                                            "pyocd list; "
                                            "lsusb -v; "