fix an error where the wait group never completes on uninitialized repo

cmd/mgfetch/mgfetch.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"os"
 	"time"
 
 	git "github.com/go-git/go-git/v5"
@@ -12,12 +13,16 @@ import (
 type Repo git.Repository
 
 func main() {
-	year := time.Now().Year() - 1
+	year := time.Now().Year()
 	authors := []string{"Groot"}
 	mr, err := commits.GetMRRepos()
 	if err != nil {
 		panic(err)
 	}
+	if len(mr) == 0 {
+		fmt.Println("found no repos!")
+		os.Exit(1)
+	}
 	gfreq, err := mr.FrequencyChan(year, authors)
 	if err != nil {
 		panic(err)