ci: report how to install what this run built

Author: ariesclark

.github/workflows/ci.yaml

@@ -10,12 +10,18 @@ on:
         required: false
         type: string
         default: main
+    outputs:
+      artifact:
+        description: Download URL for the generated SDK.
+        value: ${{ jobs.generate.outputs.artifact }}
 
 name: CI
 
 jobs:
   generate:
     runs-on: ubuntu-latest
+    outputs:
+      artifact: ${{ steps.upload.outputs.artifact-url }}
     steps:
       - uses: actions/checkout@v7
         with:
@@ -30,7 +36,8 @@ jobs:
 
       - run: bash ./generate.sh openapi-legacy.yaml
 
-      - uses: actions/upload-artifact@v7
+      - id: upload
+        uses: actions/upload-artifact@v7
         with:
           name: generated-java
           path: .