Cleanup clang-tidy warning about enum sizes

src/catch2/catch_tostring.cpp

@@ -22,7 +22,10 @@ namespace Detail {
         const int hexThreshold = 255;
 
         struct Endianness {
-            enum Arch { Big, Little };
+            enum Arch : uint8_t {
+                Big,
+                Little
+            };
 
             static Arch which() {
                 int one = 1;

src/catch2/reporters/catch_reporter_console.cpp

@@ -214,7 +214,7 @@ struct RowBreak {};
 struct OutputFlush {};
 
 class Duration {
-    enum class Unit {
+    enum class Unit : uint8_t {
         Auto,
         Nanoseconds,
         Microseconds,
@@ -286,7 +286,10 @@ public:
 };
 } // end anon namespace
 
-enum class Justification { Left, Right };
+enum class Justification : uint8_t {
+    Left,
+    Right
+};
 
 struct ColumnInfo {
     std::string name;