Update UPGRADE.md

Co-authored-by: Jan Góralski <[email protected]>

Author: GSadee

UPGRADE.md

@@ -1,6 +1,6 @@
 ## UPGRADE FOR `1.13.x`
 
-### FROM `1.12.x` to `1.12.x`
+### FROM `1.12.x` to `1.13.x`
 
 The `Sylius\Resource\Exception\VariantWithNoOptionsValuesException` and `Sylius\Component\Resource\Exception\VariantWithNoOptionsValuesException` 
 classes have been deprecated and will be removed in `2.0`.