Docs: Update readme re: branch name 4-stable

README.md

@@ -10,12 +10,11 @@ has been destroyed.
 
 | Version        | Documentation |
 | -------------- | ------------- |
-| 5              | /~https://github.com/airblade/paper_trail/blob/master/README.md |
-| 4.1            | /~https://github.com/airblade/paper_trail/blob/4.1-stable/README.md |
-| 4.0            | /~https://github.com/airblade/paper_trail/blob/4.0-stable/README.md |
+| 5              | /~https://github.com/airblade/paper_trail/blob/master/README.md     |
+| 4              | /~https://github.com/airblade/paper_trail/blob/4-stable/README.md   |
 | 3              | /~https://github.com/airblade/paper_trail/blob/3.0-stable/README.md |
 | 2              | /~https://github.com/airblade/paper_trail/blob/2.7-stable/README.md |
-| 1              | /~https://github.com/airblade/paper_trail/blob/rails2/README.md |
+| 1              | /~https://github.com/airblade/paper_trail/blob/rails2/README.md     |
 
 ## Table of Contents
 
@@ -56,7 +55,7 @@ has been destroyed.
 | paper_trail    | branch     | tags   | ruby     | activerecord |
 | -------------- | ---------- | ------ | -------- | ------------ |
 | 5              | master     | v5.x   | >= 1.9.3 | >= 3.0, < 6  |
-| 4              | 4.0-stable | v4.x   | >= 1.8.7 | >= 3.0, < 6  |
+| 4              | 4-stable   | v4.x   | >= 1.8.7 | >= 3.0, < 6  |
 | 3              | 3.0-stable | v3.x   | >= 1.8.7 | >= 3.0, < 5  |
 | 2              | 2.7-stable | v2.x   | >= 1.8.7 | >= 3.0, < 4  |
 | 1              | rails2     | v1.x   | >= 1.8.7 | >= 2.3, < 3  |