sklearn: switch 1.9 config to upstream master + gamma release env

Author: jinyan-li1

.github/config/image/sklearn/sagemaker-1.9-0.yml

@@ -18,14 +18,12 @@ build:
   target: "sklearn-sagemaker"
   base_image: "amazonlinux:2023"
   python_version: "3.12"
-  # Temporary — points at branch on upstream master repo for testing.
-  # Flip to "master" once upstream PR merges + before merging this DLC PR.
-  sklearn_container_branch: "feat/upgrade-sklearn-1.9"
+  sklearn_container_branch: "master"
 
 release:
   release: false
   force_release: false
   public_registry: false
   private_registry: true
   enable_soci: false
-  environment: "production"
+  environment: "gamma"

.github/workflows/sklearn.dispatch-release.yml

@@ -7,7 +7,7 @@ on:
         description: "Path to image config YAML"
         required: true
         type: string
-        default: ".github/config/image/sklearn/sagemaker-1.4-2-py312.yml"
+        default: ".github/config/image/sklearn/sagemaker-1.9-0.yml"
 
 concurrency:
   group: ${{ github.workflow }}-${{ inputs.config-file }}