Use upstream slack-go/slack again (#1018)

vendor/github.com/slack-go/slack/dialog_text.go

@@ -0,0 +1,59 @@
+package slack
+
+// TextInputSubtype Accepts email, number, tel, or url. In some form factors, optimized input is provided for this subtype.
+type TextInputSubtype string
+
+// TextInputOption handle to extra inputs options.
+type TextInputOption func(*TextInputElement)
+
+const (
+	// InputSubtypeEmail email keyboard
+	InputSubtypeEmail TextInputSubtype = "email"
+	// InputSubtypeNumber numeric keyboard
+	InputSubtypeNumber TextInputSubtype = "number"
+	// InputSubtypeTel Phone keyboard
+	InputSubtypeTel TextInputSubtype = "tel"
+	// InputSubtypeURL Phone keyboard
+	InputSubtypeURL TextInputSubtype = "url"
+)
+
+// TextInputElement subtype of DialogInput
+//	https://api.slack.com/dialogs#option_element_attributes#text_element_attributes
+type TextInputElement struct {
+	DialogInput
+	MaxLength int              `json:"max_length,omitempty"`
+	MinLength int              `json:"min_length,omitempty"`
+	Hint      string           `json:"hint,omitempty"`
+	Subtype   TextInputSubtype `json:"subtype"`
+	Value     string           `json:"value"`
+}
+
+// NewTextInput constructor for a `text` input
+func NewTextInput(name, label, text string, options ...TextInputOption) *TextInputElement {
+	t := &TextInputElement{
+		DialogInput: DialogInput{
+			Type:  InputTypeText,
+			Name:  name,
+			Label: label,
+		},
+		Value: text,
+	}
+
+	for _, opt := range options {
+		opt(t)
+	}
+
+	return t
+}
+
+// NewTextAreaInput constructor for a `textarea` input
+func NewTextAreaInput(name, label, text string) *TextInputElement {
+	return &TextInputElement{
+		DialogInput: DialogInput{
+			Type:  InputTypeTextArea,
+			Name:  name,
+			Label: label,
+		},
+		Value: text,
+	}
+}