CI: modernize macos builds to macos-15

macos-15 support was announced few months ago: https://github.com/github/roadmap/issues/986

diff --git a/.github/matrix.py b/.github/matrix.py
index fb467c32226a4c433deb7affd7589ffd5706c218..f90bbac4e6beed7e7899fd0a6b6cdbd9f15d9256 100755 (executable)
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -233,7 +233,7 @@ def main(ref_name):
     if "haproxy-" in ref_name:
         os = "macos-13"     # stable branch
     else:
-        os = "macos-14"     # development branch
+        os = "macos-15"     # development branch
 
     TARGET = "osx"
     for CC in ["clang"]: