Update dependencies and vendor (#1761)

vendor/github.com/labstack/echo/v4/context_fs_go1.16.go

@@ -0,0 +1,52 @@
+//go:build go1.16
+// +build go1.16
+
+package echo
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"net/http"
+	"path/filepath"
+)
+
+func (c *context) File(file string) error {
+	return fsFile(c, file, c.echo.Filesystem)
+}
+
+// FileFS serves file from given file system.
+//
+// When dealing with `embed.FS` use `fs := echo.MustSubFS(fs, "rootDirectory") to create sub fs which uses necessary
+// prefix for directory path. This is necessary as `//go:embed assets/images` embeds files with paths
+// including `assets/images` as their prefix.
+func (c *context) FileFS(file string, filesystem fs.FS) error {
+	return fsFile(c, file, filesystem)
+}
+
+func fsFile(c Context, file string, filesystem fs.FS) error {
+	f, err := filesystem.Open(file)
+	if err != nil {
+		return ErrNotFound
+	}
+	defer f.Close()
+
+	fi, _ := f.Stat()
+	if fi.IsDir() {
+		file = filepath.ToSlash(filepath.Join(file, indexPage)) // ToSlash is necessary for Windows. fs.Open and os.Open are different in that aspect.
+		f, err = filesystem.Open(file)
+		if err != nil {
+			return ErrNotFound
+		}
+		defer f.Close()
+		if fi, err = f.Stat(); err != nil {
+			return err
+		}
+	}
+	ff, ok := f.(io.ReadSeeker)
+	if !ok {
+		return errors.New("file does not implement io.ReadSeeker")
+	}
+	http.ServeContent(c.Response(), c.Request(), fi.Name(), fi.ModTime(), ff)
+	return nil
+}