Rename file

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>

Author: aggarg

.github/3P_TOOLS.md renamed to .github/third_party_tools.md

@@ -182,5 +182,5 @@ Note that only the FreeRTOS-Kernel Source Files, [include](include),
 files are checked for proper spelling, and formatting at this time.
 
 ## Third Party Tools
-Visit [this link](.github/3P_TOOLS.md) for detailed information about
+Visit [this link](.github/third_party_tools.md) for detailed information about
 third-party tools with FreeRTOS support.