Update variant2 from develop

boost-commitbot · boost-commitbot · commit a7792ea24190 · 2026-01-01T16:06:02.000Z
diff --git a/libs/variant2 b/libs/variant2
@@ -1 +1 @@
-Subproject commit f267609ad6f5dac4aa2d664d613701b50ede0404
+Subproject commit 540354878cf216a48bb155e70569d78679118d08
