fix: typo (#24)

fix(typo): Found via `codespell -L anc,ths,wit`

Author: kianmeng

src/model/marc_relators.go

@@ -260,7 +260,7 @@ var Relator = map[string]string{
 	"sfx":"special effects provider",
 	"sgd":"stage director",
 	"sgn":"signer",
-	"sht":"spporting host",
+	"sht":"supporting host",
 	"sll":"seller",
 	"sng":"singer",
 	"spk":"speaker",