Update upstream to jdk21u

.github/workflows/refresh-jdk.yml

@@ -4,7 +4,7 @@ on:
     - cron: '0 8 * * *'
   workflow_dispatch:
 env:
-  UPSTREAM_REMOTE: https://github.com/openjdk/jdk21
+  UPSTREAM_REMOTE: https://github.com/openjdk/jdk21u
   LOCAL_BRANCH: develop
 jobs:
     refresh-jdk:

README.md

@@ -6,7 +6,7 @@ Corretto is used internally at Amazon for production services.
 With Corretto, you can develop and run Java applications
 on operating systems such as Linux, Windows, and macOS.
 
-This repository is used to track [OpenJDK 21](https://github.com/openjdk/jdk21).
+This repository is used to track [OpenJDK 21u](https://github.com/openjdk/jdk21u).
 Please look at the branches section for more information on Feature Releases.
 
 Documentation is available at [https://docs.aws.amazon.com/corretto](https://docs.aws.amazon.com/corretto).
@@ -18,7 +18,7 @@ Please read these files: "LICENSE", "ADDITIONAL_LICENSE_INFO", "ASSEMBLY_EXCEPTI
 ### Branches
 
 _develop_
-: The default branch. The branch that consumes development and patches to upstream [openjdk/jdk21](https://github.com/openjdk/jdk21). Corretto builds are generated from this branch.
+: The default branch. The branch that consumes development and patches to upstream [openjdk/jdk21u](https://github.com/openjdk/jdk21u). Corretto builds are generated from this branch.
 
 ### OpenJDK Readme
 ```