mysql: change collation of tag table

utf8mb4_unicode_ci considers that 'caché' is equal to 'cache' which
can lead to attaching incorrect tags to entries. This issue is due to
some unicode normalization done by MySQL.

utf8mb4_bin makes no unicode normalization, letting wallabag to consider
'cache' and 'caché' as two different tags.

We change the collation of the whole table as Doctrine does not support
setting a collation on a column for a specific platform (it tries to
apply utf8mb4_bin even for pgsql and sqlite).

Fixes #3302

Signed-off-by: Kevin Decherf <kevin@kdecherf.com>

src/Wallabag/CoreBundle/Entity/Tag.php

@@ -13,7 +13,10 @@ use JMS\Serializer\Annotation\XmlRoot;
  * Tag.
  *
  * @XmlRoot("tag")
- * @ORM\Table(name="`tag`")
+ * @ORM\Table(
+ *     name="`tag`",
+ *     options={"collate"="utf8mb4_bin", "charset"="utf8mb4"},
+ * )
  * @ORM\Entity(repositoryClass="Wallabag\CoreBundle\Repository\TagRepository")
  * @ExclusionPolicy("all")
  */