fix: use POSIX equality operator

Author: typicode

husky.sh

@@ -28,7 +28,7 @@ if [ -z "$husky_skip_init" ]; then
     echo "husky - $hook_name hook exited with code $exitCode (error)"
   fi
 
-  if [ $exitCode == 127 ]; then
+  if [ $exitCode = 127 ]; then
     echo "husky - command not found in PATH=$PATH"
   fi