[cd] Bump CIRCT from firtool-1.85.0 to firtool-1.86.0 (#4401)

This is an automated commit generated by the `circt/update-circt` GitHub
Action.

Co-authored-by: chiselbot <chiselbot@users.noreply.github.com>

etc/circt.json

@@ -1,3 +1,3 @@
 {
-  "version": "firtool-1.85.0"
+  "version": "firtool-1.86.0"
 }