Update BUILD_OSS to 5268

Typing quality
* Added  鵼(ぬえ) and 喃(のう) to the word dictionary.

Linux
* Fixed the crash issue of the candidate window UI (google#820)

Windows
* Enabled the candidate window to respect the vertical writing mode (google#362)
* Updated InputScope mapping to be compatible with MS-IME as of Windows 11 22H2 (google#818, google#826)
* Addressed the issue of no response on MS-Word (google#819)
* Enabled the candidate window to consider per-monitor DPI settings (google#832)

Build
* Enabled C++20 (google#783)
* Switched to Qt 6.6.0 for Windows and macOS (google#833)
* Reduced Qt6 binary size (google#822)
* macOS: Fixed the non executable error of GUI tools with GYP
* Windows: Stopped specifying /BASE option (google#834)
* Windows: Enabled Hardware Enforced Stack Protection (google#835)
* Windows: Set default dependent load flags to Mozc executables for Windows (google#836)
* Windows: Removed the dependency on CoCreateInpustance from mozc_tip dlls (google#837)

PiperOrigin-RevId: 576830216

src/data/version/mozc_version_template.bzl

@@ -32,7 +32,7 @@ MAJOR = 2
 MINOR = 29
 
 # BUILD number used for the OSS version.
-BUILD_OSS = 5250
+BUILD_OSS = 5268
 
 # Number to be increased. This value may be replaced by other tools.
 BUILD = BUILD_OSS