Bump versions to 1.2.3 for release

man/meson.1

@@ -1,4 +1,4 @@
-.TH MESON "1" "September 2023" "meson 1.2.2" "User Commands"
+.TH MESON "1" "October 2023" "meson 1.2.3" "User Commands"
 .SH NAME
 meson - a high productivity build system
 .SH DESCRIPTION

mesonbuild/coredata.py

@@ -59,7 +59,7 @@ if T.TYPE_CHECKING:
 #
 # Pip requires that RCs are named like this: '0.1.0.rc1'
 # But the corresponding Git tag needs to be '0.1.0rc1'
-version = '1.2.2'
+version = '1.2.3'
 
 # The next stable version when we are in dev. This is used to allow projects to
 # require meson version >=1.2.0 when using 1.1.99. FeatureNew won't warn when