Update _index.md

Added RME and CCA to open taxonomy metadata

Author: madeline-underwood

content/learning-paths/cross-platform/cca_rme/_index.md

@@ -32,6 +32,8 @@ tools_software_languages:
     - Coding
     - Trusted Firmware
     - Arm Development Studio
+    - RME
+    - CCA
 
 ### Cross-platform metadata only
 shared_path: true