Add a limit to replace via regexp (#946)

When using [Replace with Regexp](https://robo.li/tasks/File/#replace) there is no possibility to add a limit to the replaced items. This would be useful for instance when I replace version numbers in the DocBlock of fields and we want to replace only a single occurence.

for #123

src/Task/File/Replace.php

@@ -44,6 +44,11 @@ class Replace extends BaseTask
      */
     protected $from;
 
+    /**
+     * @var integer
+     */
+    protected $limit = -1;
+
     /**
      * @var string|string[]
      */
@@ -112,6 +117,19 @@ public function regex($regex)
         return $this;
     }
 
+    /**
+     * If used with $this->regexp() how many counts will be replaced
+     *
+     * @param int $limit
+     *
+     * @return $this
+     */
+    public function limit($limit)
+    {
+        $this->limit = $limit;
+        return $this;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -124,7 +142,7 @@ public function run()
 
         $text = file_get_contents($this->filename);
         if ($this->regex) {
-            $text = preg_replace($this->regex, $this->to, $text, -1, $count);
+            $text = preg_replace($this->regex, $this->to, $text, $this->limit, $count);
         } else {
             $text = str_replace($this->from, $this->to, $text, $count);
         }