Fix msvc warning treated as error

src/snippets/snippet.cpp

@@ -9,6 +9,7 @@
 #include <iostream>
 
 #include "../utils/common.hpp"
+#include "../utils/utils.hpp"
 
 namespace cpptrace {
 namespace detail {
@@ -36,7 +37,7 @@ namespace detail {
                     }
                     // else load file
                     file.seekg(0, std::ios::beg);
-                    contents.resize(size);
+                    contents.resize(to<std::size_t>(size));
                     if(!file.read(&contents[0], size)) {
                         // error ...
                     }