Switching to tflite-micro repository

Change-Id: I2e168e3cac10785b3abce4d85b51acecd7aa23f5
diff --git a/externals.json b/externals.json
index aa8feb1..232ab15 100644
--- a/externals.json
+++ b/externals.json
@@ -40,9 +40,9 @@
             "revision": "main"
         },
         {
-            "path": "core_software/tensorflow",
-            "fetchurl": "https://github.com/tensorflow/tensorflow",
-            "revision": "master"
+            "path": "core_software/tflite_micro",
+            "fetchurl": "https://github.com/tensorflow/tflite-micro",
+            "revision": "main"
         },
         {
             "path": "linux_driver_stack",