Added header to socpull

tools/socpull

+#-----------------------------------------------------------------------------
+# SoC Labs SoCPull Script 
+# - Pull latest updates to all Repositories in a project
+# A joint work commissioned on behalf of SoC Labs, under Arm Academic Access license.
+#
+# Contributors
+#
+# David Mapstone (d.a.mapstone@soton.ac.uk)
+#
+# Copyright  2023, SoC Labs (www.soclabs.org)
+#-----------------------------------------------------------------------------
 #!/bin/bash
 
 # Update all Submodules to latest commit