Update progress.py: doc: Progress.default_columns -> Progress.get_def… (#3170)

* Update progress.py: doc: Progress.default_columns -> Progress.get_default_columns

Update progress.py: doc: 
Progress.default_columns -> Progress.get_default_columns

* Update CONTRIBUTORS.md

add bwagner (myself) to contributors

Author: bwagner

CONTRIBUTORS.md

@@ -70,4 +70,5 @@ The following people have contributed to the development of Rich:
 - [Ke Sun](https://github.com/ksun212)
 - [Qiming Xu](https://github.com/xqm32)
 - [James Addison](https://github.com/jayaddison)
-- [Pierro](https://github.com/xpierroz)
+- [Pierro](https://github.com/xpierroz)
+- [Bernhard Wagner](https://github.com/bwagner)

rich/progress.py

@@ -1113,7 +1113,7 @@ def get_default_columns(cls) -> Tuple[ProgressColumn, ...]:
 
             progress = Progress(
                 SpinnerColumn(),
-                *Progress.default_columns(),
+                *Progress.get_default_columns(),
                 "Elapsed:",
                 TimeElapsedColumn(),
             )