fix: incorrect variable name

Author: bencegadanyi1-nhs

.github/workflows/cdk_package_code.yml

@@ -44,7 +44,7 @@ jobs:
       - name: Install asdf dependencies in .tool-versions
         uses: asdf-vm/actions/install@1902764435ca0dd2f3388eea723a4f92a4eb8302
         with:
-          asdf_branch: v0.18.0
+          asdf_version: v0.18.0
         env:
           PYTHON_CONFIGURE_OPTS: --enable-shared