[llvm] [CI] Bump Linux Contaienr LLVM to 21.1.0 (PR #155658)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-github-workflow

Author: Aiden Grossman (boomanaiden154)

<details>
<summary>Changes</summary>

Now that a new release has come out, we should bump the version of the toolchain in the container to keep up to date.

---
Full diff: https://github.com/llvm/llvm-project/pull/155658.diff


1 Files Affected:

- (modified) .github/workflows/containers/github-action-ci/Dockerfile (+1-1) 


``````````diff
diff --git a/.github/workflows/containers/github-action-ci/Dockerfile b/.github/workflows/containers/github-action-ci/Dockerfile
index f8e68ac01b168..f5422b4527576 100644
--- a/.github/workflows/containers/github-action-ci/Dockerfile
+++ b/.github/workflows/containers/github-action-ci/Dockerfile
@@ -2,7 +2,7 @@ FROM docker.io/library/ubuntu:24.04 as base
 ENV LLVM_SYSROOT=/opt/llvm
 
 FROM base as stage1-toolchain
-ENV LLVM_VERSION=20.1.8
+ENV LLVM_VERSION=21.1.0
 
 RUN apt-get update && \
     apt-get install -y \

``````````

</details>


https://github.com/llvm/llvm-project/pull/155658