Updated "Key Dates" with 3.1.0 support.

Author: Dean Wampler

README.md

@@ -27,6 +27,7 @@
 | May 15, 2021      | Scala `3.0.0` final  updates. Almost done! |
 | May 22, 2021      | _Final_ updates for _Programming Scala, Third Edition_! |
 | July 24, 2021     | Scala 3.0.1. Notes on using IntelliJ. |
+| November 6, 2021  | Scala 3.1.0 and a fix for locale settings ([PR 42](https://github.com/deanwampler/programming-scala-book-code-examples/pull/42)). |
 
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