Fix sheet name escaping

Sheet names are stored as attributes of an XML entity. We therefore need a different escaping strategy, escaping quotes.

tests/Spout/Common/Helper/Escaper/ODSTest.php

@@ -17,7 +17,7 @@ class ODSTest extends TestCase
     {
         return [
             ['test', 'test'],
-            ['carl\'s "pokemon"', 'carl\'s "pokemon"'],
+            ['carl\'s "pokemon"', 'carl's "pokemon"'],
             ["\n", "\n"],
             ["\r", "\r"],
             ["\t", "\t"],