docs: increase trainig project version number

docs/language/ql-training/conf.py

@@ -86,9 +86,9 @@ htmlhelp_basename = 'CodeQL training'
 # built documents.
 #
 # The short X.Y version.
-version = u'1.22'
+version = u'1.23'
 # The full version, including alpha/beta/rc tags.
-release = u'1.22'
+release = u'1.23'
 copyright = u'2019 Semmle Ltd'
 author = u'Semmle Ltd'