Updated README for rails/ruby compatibilty matrix

[git-p4: depot-paths = "//src/minitest/dev/": change = 13583]

README.rdoc

@@ -407,37 +407,34 @@ Using our example above, here is how we might implement MyCI:
 
 Minitest is a dependency of rails, which until fairly recently had an
 overzealous backwards compatibility policy. As such, I'm stuck
-supporting versions of ruby that are long past EOL. Once rails 5.2 is
-dropped (hopefully April 2021), I get to drop a bunch of versions of
-ruby that I have to currently test against.
+supporting versions of ruby that are long past EOL. Hopefully I'll be
+able to support only current versions of ruby sometime in the near
+future.
 
-(As of 2021-01-31)
+(As of 2022-11-29)
 
 Current versions of rails: (https://endoflife.date/rails)
 
   | rails | min ruby | rec ruby | minitest | status   |
   |-------+----------+----------+----------+----------|
-  |   7.0 | >= 2.7   |      3.0 | >= 5.1   | Future   |
-  |   6.1 | >= 2.5   |      3.0 | >= 5.1   | Current  |
+  | 7.0.0 | >= 2.7   |      3.1 | >= 5.1   | Current  |
+  |   6.1 | >= 2.5   |      3.0 | >= 5.1   | Maint    |
   |   6.0 | >= 2.5   |      2.6 | >= 5.1   | Security |
-  |   5.2 | >= 2.2.2 |      2.5 | ~> 5.1   | Security | EOL @railsconf 2021?
+  |   5.2 | >= 2.2.2 |      2.5 | ~> 5.1   | EOL      |
 
 Current versions of ruby: (https://endoflife.date/ruby)
 
   | ruby | Status  |   EOL Date |
   |------+---------+------------|
-  |  3.0 | Current | 2024-03-31 |
-  |  2.7 | Maint   | 2023-03-31 |
-  |  2.6 | Maint*  | 2022-03-31 |
+  |  3.1 | Current | 2025-12-25 |
+  |  3.0 | Maint   | 2024-03-31 |
+  |  2.7 | Maint*  | 2023-03-31 |
+  |  2.6 | EOL     | 2022-03-31 |
   |  2.5 | EOL     | 2021-03-31 |
-  |  2.4 | EOL     | 2020-03-31 |
-  |  2.3 | EOL     | 2019-03-31 |
-  |  2.2 | EOL     | 2018-03-31 |
 
 See also:
 
 * https://www.fastruby.io/blog/ruby/rails/versions/compatibility-table.html
-* https://jamesjeffersconsulting.com/ruby-rails-version-matrix/
 
 === How to test SimpleDelegates?