I'm transitioning a Drupal 6 site to Drupal 8.1 so following the official instructions, I set up a new install in its own directory. Since this is only one site, I followed the instructions to put my database credentials in sites/default/default.settings.php after the declaration of the $databases array.
drush --status returns the following.
Drush version : 8.1-dev Drush temp directory : /tmp Drush configuration : Drush alias files : Drupal root : /media/psf/Home/apps/newp Drupal Settings File : MISSING
Since this Drupal is 8.1-dev that must mean I need to upgrade it. Since this is a global install using Composer, I run
composer global update.
Your requirements could not be resolved to an installable set of packages drush/drush dev-master requires codegyre/robo ~1.0.0-beta1
Checking the drush-ops page on github doesn't show any anomalies like this nor my Google search.
What am I overlooking?