build: fix duet commit message integration

Co-authored-by: Max Pleaner <maxpleaner@hover.to>

Author: jrolfs

.husky/prepare-commit-msg

@@ -3,6 +3,6 @@
 # Automates pair commits with git-duet
 # See: https://github.com/git-duet/git-duet/#co-authored-by-trailer-support
 
-if [ $(git help -a | grep duet-prepare-msg) ]; then
+if [ $(git help -a | grep duet-prepare-commit-msg) ]; then
   exec git duet-prepare-commit-msg "$@"
 fi