Add icalendar zoneinfo branch + tzdata verison pin.

Ref: collective/icalendar#623

checkouts.cfg

@@ -10,6 +10,7 @@ auto-checkout =
     plone.app.upgrade
     Products.CMFPlone
 # These packages are manually added, or automatically added by mr.roboto:
+    icalendar
     plone.restapi
     plone.base
     plone.app.iterate

sources.cfg

@@ -41,7 +41,7 @@ diazo                               = git ${remotes:plone}/diazo.git pushurl=${r
 five.customerize                    = git ${remotes:zope}/five.customerize.git pushurl=${remotes:zope_push}/five.customerize.git branch=master
 five.intid                          = git ${remotes:plone}/five.intid.git pushurl=${remotes:plone_push}/five.intid.git branch=master
 i18ndude                            = git ${remotes:collective}/i18ndude.git pushurl=${remotes:collective_push}/i18ndude.git branch=master
-icalendar                           = git ${remotes:collective}/icalendar.git pushurl=${remotes:collective_push}/icalendar.git branch=master
+icalendar                           = git ${remotes:collective}/icalendar.git pushurl=${remotes:collective_push}/icalendar.git branch=zoneinfo
 Plone                               = git ${remotes:plone}/Plone.git pushurl=${remotes:plone_push}/Plone.git branch=master
 plone.alterego                      = git ${remotes:plone}/plone.alterego.git pushurl=${remotes:plone_push}/plone.alterego.git branch=master
 plone.api                           = git ${remotes:plone}/plone.api.git pushurl=${remotes:plone_push}/plone.api.git branch=master

versions.cfg

@@ -246,6 +246,7 @@ trio-websocket = 0.11.1
 types-PyYAML = 6.0.12.10
 types-toml = 0.10.8.5
 typing-extensions = 4.9.0
+tzdata = 2024.1
 Unidecode = 1.3.8
 urllib3-secure-extra = 0.1.0
 watchdog = 3.0.0