Tolerate "dot" directories when checking if dir is empty

Many users will be running version control; we should ignore .git
directories also therefore.  We ignore all directories starting with
"." (just as we ignore all files starting with ".").

Also add go.sum to ignore list, as go.mod is already ignored.

Co-authored-by: Adrián <Adirio@users.noreply.github.com>

pkg/plugins/golang/v3/init.go

@@ -207,9 +207,16 @@ func checkDir() error {
 			if err != nil {
 				return err
 			}
-			if info.Name() != "go.mod" && !strings.HasPrefix(info.Name(), ".") {
+			// Allow the whole .git directory tree
+			if info.IsDir() && strings.HasPrefix(info.Name(), ".") && info.Name() != "." {
+				return filepath.SkipDir
+			}
+			// Also allow go.mod and dot-files
+			if info.Name() != "go.mod" && info.Name() != "go.sum" && !strings.HasPrefix(info.Name(), ".") {
 				return fmt.Errorf(
-					"target directory is not empty (only go.mod and files with the prefix \".\" are allowed); found existing file %q",
+					"target directory is not empty "+
+						"(only go.mod, go.sum, and files and directories with the prefix \".\" are allowed); "+
+						"found existing file %q",
 					path)
 			}
 			return nil