Rename fetch_sets to comply to Golang standards

src/serra/scryfall.go

@@ -211,7 +211,7 @@ func fetchCard(path string) (*Card, error) {
 	return val, nil
 }
 
-func fetch_sets() (*SetList, error) {
+func fetchSets() (*SetList, error) {
 	// TODO better URL Building...
 	resp, err := http.Get("https://api.scryfall.com/sets")
 	if err != nil {

src/serra/update.go

@@ -49,7 +49,7 @@ var updateCmd = &cobra.Command{
 				{"usdfoil", bson.D{{"$sum", bson.D{{"$multiply", bson.A{"$last_price.usd_foil", "$serra_count_foil"}}}}}},
 			}}}
 
-		sets, _ := fetch_sets()
+		sets, _ := fetchSets()
 		for _, set := range sets.Data {
 
 			// When downloading new sets, PriceList needs to be initialized