tests: fix missing include

sedmicha · Lukas955 · commit ac2dace3a95f · 2024-01-11T13:14:48.000+01:00
diff --git a/tests/unit_tests/converters/to_string.cpp b/tests/unit_tests/converters/to_string.cpp
@@ -48,6 +48,7 @@
 #include <string>
 #include <memory>
 #include <cmath>
+#include <array>
 
 #include <iomanip> // setprecision
 #include <sstream> // stringstream
