examples: cleanup curl includes

Only <curl/curl.h> is needed typically and curl/types.h has been removed

docs/examples/postit2.c

@@ -37,8 +37,6 @@
 #include <string.h>
 
 #include <curl/curl.h>
-#include <curl/types.h>
-#include <curl/easy.h>
 
 int main(int argc, char *argv[])
 {