Add .clang-format file

Using clang-format version 12.0.0

tests/rand_int.h

@@ -8,7 +8,7 @@
 #include <random>
 #include <type_traits>
 
-template <typename T>
+template<typename T>
 T RandInt(T min, T max) {
     static_assert(std::is_integral_v<T>, "T must be an integral type.");
     static_assert(!std::is_same_v<T, signed char> && !std::is_same_v<T, unsigned char>,