core: add version 4.2.1 in ChangeLog and release notes

ChangeLog.adoc

@@ -13,6 +13,13 @@ For a list of important changes that require manual actions, please look at rele
 [[v4.3.0]]
 == Version 4.3.0 (under dev)
 
+Bug fixes::
+
+  * irc: fix random date displayed when a received message contains tags but no "time" (issue #2064)
+
+[[v4.2.1]]
+== Version 4.2.1 (2024-01-22)
+
 Bug fixes::
 
   * irc: fix random date displayed when a received message contains tags but no "time" (issue #2064)

ReleaseNotes.adoc

@@ -16,6 +16,11 @@ For a complete list of changes, please look at ChangeLog.
 
 No release notes.
 
+[[v4.2.1]]
+== Version 4.2.1 (2024-01-22)
+
+No release notes.
+
 [[v4.2.0]]
 == Version 4.2.0 (2024-01-21)
 

version.sh

@@ -39,7 +39,7 @@
 #     devel-number   the devel version as hex number ("0x04010000" for "4.1.0-dev")
 #
 
-weechat_stable="4.2.0"
+weechat_stable="4.2.1"
 weechat_devel="4.3.0-dev"
 
 stable_major=$(echo "${weechat_stable}" | cut -d"." -f1)