using StringSlice instead of []string for Files

DOCS.md

@@ -13,8 +13,7 @@ Sample configuration:
 publish:
   github_release:
     api_key: my_github_api_key
-    files:
-      - dist/*
+    files: dist/*
     checksum: sha1
 ```
 
@@ -26,6 +25,7 @@ publish:
     api_key: my_github_api_key
     files:
       - dist/*
+      - bin/binary.exe
     checksum:
       - md5
       - sha1

main.go

@@ -60,7 +60,7 @@ func main() {
 	}
 
 	var files []string
-	for _, glob := range vargs.Files {
+	for _, glob := range vargs.Files.Slice() {
 		globed, err := filepath.Glob(glob)
 		if err != nil {
 			fmt.Printf("Failed to glob %s\n", glob)

types.go

@@ -7,6 +7,6 @@ type Params struct {
 	BaseURL   string            `json:"base_url"`
 	UploadURL string            `json:"upload_url"`
 	APIKey    string            `json:"api_key"`
-	Files     []string          `json:"files"`
+	Files     drone.StringSlice `json:"files"`
 	Checksum  drone.StringSlice `json:"checksum"`
 }