Update AntiTamper.lua - lua 5.1.5 debug.sethook bug fix

This fix adds a "5" to the 3rd argument, as Lua 5.1.5 has a very unusual bug where if the 3rd argument doesn't exist, nothing happens.

Author: SpinnySpiwal

src/prometheus/steps/AntiTamper.lua

@@ -38,22 +38,28 @@ function AntiTamper:apply(ast, pipeline)
         local string = RandomStrings.randomString();
         code = code .. [[
             -- Anti Beautify
-            local sethook = debug and debug.sethook or function() end;
-            local allowedLine = nil;
-            local called = 0;
-            sethook(function(s, line)
-                called = called + 1;
-                if allowedLine then
-                    if allowedLine ~= line then
-                        sethook(error, "l");
-                    end
-                else
-                    allowedLine = line;
-                end
-            end, "l");
-            (function() end)();
-            (function() end)();
-            sethook();
+			local sethook = debug and debug.sethook or function() end;
+			local allowedLine = nil;
+			local called = 0;
+			sethook(function(s, line)
+				if not line then
+					return
+				end
+				called = called + 1;
+				if allowedLine then
+					if allowedLine ~= line then
+						sethook(error, "l", 5);
+					end
+				else
+					allowedLine = line;
+				end
+			end, "l", 5);
+			(function() end)();
+			(function() end)();
+			sethook();
+			if called < 2 then
+				valid = false;
+			end
             if called < 2 then
                 valid = false;
             end
@@ -173,4 +179,4 @@ end
     return ast;
 end
 
-return AntiTamper;
+return AntiTamper;