[Wasm] Set darwin toolchain version to 5.6

Author: kateinoigakukun

utils/webassembly/build-toolchain.sh

@@ -167,7 +167,7 @@ create_darwin_info_plist() {
   echo "-- Create Info.plist --"
   PLISTBUDDY_BIN="/usr/libexec/PlistBuddy"
 
-  DARWIN_TOOLCHAIN_VERSION="5.5.${YEAR}${MONTH}${DAY}"
+  DARWIN_TOOLCHAIN_VERSION="5.6.${YEAR}${MONTH}${DAY}"
   BUNDLE_PREFIX="org.swiftwasm"
   DARWIN_TOOLCHAIN_BUNDLE_IDENTIFIER="${BUNDLE_PREFIX}.${YEAR}${MONTH}${DAY}"
   DARWIN_TOOLCHAIN_DISPLAY_NAME_SHORT="Swift for WebAssembly Snapshot"