feat: show call for conference volunteers

Author: phette23

_data/conf.yml

@@ -421,9 +421,9 @@ volunteer-dutyoff:
 
 # for volunteers during conference like MCs, mic-minders, etc.
 volunteer-onsite:
-  show: false
-  url: ''
-  end-date: ''
+  show: true
+  url: https://wiki.code4lib.org/Code4Lib_2026_Conference_Volunteers
+  end-date:
 
 ################
 # Scholarships

_includes/homepage/pre_conference.html

@@ -244,7 +244,7 @@ <h3 class="expo">Volunteering</h3>
                     title='Volunteer at Code4Lib'
                     end-date=site.data.conf.volunteer-onsite.end-date
                     url=site.data.conf.volunteer-onsite.url
-                    url-text='Volunteer for Onsite Conference'
+                    url-text='Volunteer Onsite at Code4Lib'
                 %}
             {% endif %}
             {% if site.data.conf.volunteer-call.show %}