feat(core,windows): update C++ SDK to 12.7.0 (#17238)

Author: Lyokone

packages/firebase_core/firebase_core/windows/CMakeLists.txt

@@ -4,7 +4,7 @@
 # customers of the plugin.
 cmake_minimum_required(VERSION 3.14)
 
-set(FIREBASE_SDK_VERSION "12.0.0")
+set(FIREBASE_SDK_VERSION "12.7.0")
 
 if (EXISTS $ENV{FIREBASE_CPP_SDK_DIR}/include/firebase/version.h)
     file(READ "$ENV{FIREBASE_CPP_SDK_DIR}/include/firebase/version.h" existing_version)