picolibc: Update to version 1.8.7

Integrate new upstream release.
Include strnlen_s and aarch64 cmake fixes.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

west.yml

@@ -315,7 +315,7 @@ manifest:
         - debug
     - name: picolibc
       path: modules/lib/picolibc
-      revision: 764ef4e401a8f4c6a86ab723533841f072885a5b
+      revision: 06bde1fd7531b1f788f6e42b6f7b358c0fe4f814
     - name: segger
       revision: b011c45b585e097d95d9cf93edf4f2e01588d3cd
       path: modules/debug/segger