Bump fuzztest to the latest tag (#3407)

cmake/Modules/LocalFuzztest.cmake

diff --git a/cmake/Modules/LocalFuzztest.cmake b/cmake/Modules/LocalFuzztest.cmake
index 732d8bb..8dc1c71 100644
--- a/cmake/Modules/LocalFuzztest.cmake
+++ b/cmake/Modules/LocalFuzztest.cmake
@@ -1,4 +1,4 @@
-set(AVIF_FUZZTEST_TAG "8fdc787e8c64066619b69f3ee9d168c00aeddab2")
+set(AVIF_FUZZTEST_TAG "2026-06-29")
 
 set(FUZZTEST_SOURCE_DIR "${AVIF_SOURCE_DIR}/ext/fuzztest")