Add bold to colors class

slither/utils/colors.py

@@ -10,6 +10,7 @@ class Colors:  # pylint: disable=too-few-public-methods
     YELLOW = "\033[93m"
     BLUE = "\033[94m"
     MAGENTA = "\033[95m"
+    BOLD = "\033[1m"
     END = "\033[0m"
 
 
@@ -83,6 +84,7 @@ yellow = partial(colorize, Colors.YELLOW)
 red = partial(colorize, Colors.RED)
 blue = partial(colorize, Colors.BLUE)
 magenta = partial(colorize, Colors.MAGENTA)
+bold = partial(colorize, Colors.BOLD)
 
 # We enable colorization by default if the output is a tty
 set_colorization_enabled(sys.stdout.isatty())