fix: update migration version to v2.0.1 and remove default value for TEXT column

internal/entity/user_entity.go

diff --git a/internal/entity/user_entity.go b/internal/entity/user_entity.go
index 5e9eed1..8aac4c7 100644
--- a/internal/entity/user_entity.go
+++ b/internal/entity/user_entity.go
@@ -60,7 +60,7 @@
 	Status         int       `xorm:"not null default 1 INT(11) status"`
 	AuthorityGroup int       `xorm:"not null default 1 INT(11) authority_group"`
 	DisplayName    string    `xorm:"not null default '' VARCHAR(30) display_name"`
-	Avatar         string    `xorm:"not null default '' TEXT avatar"`
+	Avatar         string    `xorm:"not null TEXT avatar"`
 	Mobile         string    `xorm:"not null VARCHAR(20) mobile"`
 	Bio            string    `xorm:"not null TEXT bio"`
 	BioHTML        string    `xorm:"not null TEXT bio_html"`

internal/migrations/migrations.go

diff --git a/internal/migrations/migrations.go b/internal/migrations/migrations.go
index a139395..682a7b2 100644
--- a/internal/migrations/migrations.go
+++ b/internal/migrations/migrations.go
@@ -107,7 +107,7 @@
 	NewMigration("v1.7.2", "expand avatar column length", expandAvatarColumnLength, false),
 	NewMigration("v1.8.0", "change admin menu", updateAdminMenuSettings, true),
 	NewMigration("v1.8.1", "ai feat", aiFeat, true),
-	NewMigration("v1.8.2", "change avatar type to text", updateAvatarType, false),
+	NewMigration("v2.0.1", "change avatar type to text", updateAvatarType, false),
 }
 
 func GetMigrations() []Migration {