Default to build heif support

Heif is now being widely used because of android and iphones
and it's not really nice to discover that even if I have the
library to handle heif, it's not compilling.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.16)
 
-set(KF_VERSION "6.9.0") # handled by release scripts
+set(KF_VERSION "6.10.0") # handled by release scripts
 set(KF_DEP_VERSION "6.9.0") # handled by release scripts
 project(KImageFormats VERSION ${KF_VERSION})
 
@@ -62,7 +62,7 @@ set_package_properties(libavif PROPERTIES
     PURPOSE "Required for the QImage plugin for AVIF images"
 )
 
-option(KIMAGEFORMATS_HEIF "Enable plugin for HEIF format" OFF)
+option(KIMAGEFORMATS_HEIF "Enable plugin for HEIF format" ON)
 if(KIMAGEFORMATS_HEIF)
     pkg_check_modules(LibHeif IMPORTED_TARGET libheif>=1.10.0)
 endif()