Slowness execution time output in seconds instead of milliseconds

Slow tests often run for over 1 second. The output of 1000 milliseconds or more
can be harder to read the longer the test runs. Using seconds inserts a decimal
to make output easier to read for humans.

For example, a slow test running for 12432 milliseconds displays as 12.432 seconds

src/SpeedTrap.php

@@ -209,8 +209,9 @@ protected function renderBody(): void
         for ($i = 1; $i <= $length; ++$i) {
             $label = key($slowTests);
             $time = array_shift($slowTests);
+            $seconds = $time / 1000;
 
-            echo sprintf(" %s. %sms to run %s\n", $i, $time, $label);
+            echo sprintf(" %s. %ss to run %s\n", $i, $seconds, $label);
         }
     }
 

tests/SomeSlowTest.php

@@ -33,6 +33,13 @@ public function testLongEndToEndTest()
         $this->assertTrue(true);
     }
 
+    public function testSlowTestsOverOneSecond()
+    {
+        $this->extendTime(1300);
+
+        $this->assertTrue(true);
+    }
+
     /**
      * @dataProvider provideTime
      */