RewriteEngine On
# match any URL with www and rewrite it to https without the www
RewriteCond %{HTTP_HOST} ^(www\.)(.*) [NC]
RewriteRule (.*) https://%2%{REQUEST_URI} [L,R=301]
# match urls that are non https (without the www)
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} !^(www\.)(.*) [NC]
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]