sqldb: use the new schema

We put this new schema update into the main line and change the
versions of the schema updates which are currently only available
in dev builds. The schemas need to be chronological therefore we
also need to rename the file numbers.

sqldb/migrations.go

@@ -73,6 +73,11 @@ var (
 			// schema. This is optional and can be disabled by the
 			// user if necessary.
 		},
+		{
+			Name:          "000007_invoice_add_settled_index",
+			Version:       8,
+			SchemaVersion: 7,
+		},
 	}, migrationAdditions...)
 
 	// ErrMigrationMismatch is returned when a migrated record does not