fix: errors.Join defined for go1.19 or below will not work using unsa…

…fe.String, since it is not available on previous go versions

join_go120.go

@@ -5,4 +5,16 @@ package errors
 
 import "errors"
 
-var Join = errors.Join
+// Join returns an error that wraps the given errors.
+// Any nil error values are discarded.
+// Join returns nil if every value in errs is nil.
+// The error formats as the concatenation of the strings obtained
+// by calling the Error method of each element of errs, with a newline
+// between each string.
+//
+// A non-nil error returned by Join implements the Unwrap() []error method.
+//
+// Available only for go 1.20 or superior.
+func Join(errs ...error) error {
+	return errors.Join(errs...)
+}

join_test.go → join_go120_test.go

@@ -1,3 +1,6 @@
+//go:build go1.20
+// +build go1.20
+
 package errors_test
 
 import (