Add a ref for workflow dispatch

Author: thomasjpfan

.github/workflows/wheels.yml

@@ -1,8 +1,5 @@
 name: Publish sdist and wheels
 
-env:
-  SOURCE_REF_TO_BUILD: main
-
 on:
   schedule:
     # 01:01 UTC every Monday and Thursday.
@@ -16,6 +13,11 @@ on:
       - main
   workflow_dispatch:
     inputs:
+      ref:
+        description: The scikit-learn branch, tag, or commit to build
+        required: false
+        default: main
+        type: string
       environment:
         description: Which PyPI environment to upload to, if any
         required: true
@@ -151,7 +153,7 @@ jobs:
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           repository: scikit-learn/scikit-learn
-          ref: ${{ env.SOURCE_REF_TO_BUILD }}
+          ref: ${{ github.event.inputs.ref || 'main' }}
           path: scikit-learn-src
           persist-credentials: false
 
@@ -202,7 +204,7 @@ jobs:
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           repository: scikit-learn/scikit-learn
-          ref: ${{ env.SOURCE_REF_TO_BUILD }}
+          ref: ${{ github.event.inputs.ref || 'main' }}
           path: scikit-learn-src
           persist-credentials: false