refactor(eventsub): consume date.h as submodule (#6044)

lib/twitch-eventsub-ws/include/twitch-eventsub-ws/chrono.hpp

@@ -3,7 +3,6 @@
 #include <boost/json.hpp>
 
 #include <chrono>
-#include <sstream>
 
 namespace chatterino::eventsub::lib {
 

lib/twitch-eventsub-ws/src/CMakeLists.txt

@@ -48,7 +48,12 @@ add_library(${PROJECT_NAME} STATIC ${SOURCE_FILES})
 # Generate source groups for use in IDEs
 # source_group(TREE ${CMAKE_SOURCE_DIR} FILES ${SOURCE_FILES})
 
-target_include_directories(${PROJECT_NAME} PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/../include")
+target_include_directories(${PROJECT_NAME}
+    PUBLIC
+        "${CMAKE_CURRENT_SOURCE_DIR}/../include"
+    PRIVATE
+        "${CMAKE_CURRENT_SOURCE_DIR}/../lib/date/include"
+)
 
 
 target_link_libraries(${PROJECT_NAME}

lib/twitch-eventsub-ws/src/chrono.cpp

@@ -1,6 +1,6 @@
 #include "twitch-eventsub-ws/chrono.hpp"
 
-#include "twitch-eventsub-ws/date.h"
+#include <date/date.h>
 
 #include <sstream>