Update changelog

Author: vitaut

ChangeLog.md

@@ -1,3 +1,21 @@
+# 11.1.5 - TBD
+
+- Fixed compilation with GCC 15 and C++20 modules enabled
+  (https://github.com/fmtlib/fmt/pull/4347). Thanks @tkhyn.
+
+- Worked around an ABI issue in spdlog
+  (https://github.com/fmtlib/fmt/issues/4385).
+
+- Optimized `text_style` using bit packing
+  (https://github.com/fmtlib/fmt/pull/4363). Thanks @LocalSpook.
+
+- Fixed handling of named arguments in format specs
+  (https://github.com/fmtlib/fmt/issues/4360,
+  https://github.com/fmtlib/fmt/pull/4361). Thanks @dinomight.
+
+- Added error reporting for duplicate named arguments
+  (https://github.com/fmtlib/fmt/pull/4367). Thanks @dinomight.
+
 # 11.1.4 - 2025-02-26
 
 - Fixed ABI compatibility with earlier 11.x versions on Windows