ci/update: cleanup how we get nixvim-ci's user-info

Get id, name, & email in a single `user-info` step.

.github/workflows/update.yml

@@ -50,16 +50,27 @@ jobs:
           app-id: ${{ vars.CI_APP_ID }}
           private-key: ${{ secrets.CI_APP_PRIVATE_KEY }}
 
-      - name: Get GitHub App User ID
-        id: user-id
-        run: echo "user-id=$(gh api "/users/${{ steps.app-token.outputs.app-slug }}[bot]" --jq .id)" >> "$GITHUB_OUTPUT"
+      - name: Get GitHub App user info
+        id: user-info
         env:
           GH_TOKEN: ${{ steps.app-token.outputs.token }}
+          slug: ${{ steps.app-token.outputs.app-slug }}
+        run: |
+          name="$slug[bot]"
+          id=$(gh api "/users/$name" --jq .id)
+          {
+            echo "id=$id"
+            echo "name=$name"
+            echo "email=$id+$name@users.noreply.github.com"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Configure git
+        env:
+          name: ${{ steps.user-info.outputs.name }}
+          email: ${{ steps.user-info.outputs.email }}
         run: |
-          git config --global user.name '${{ steps.app-token.outputs.app-slug }}[bot]'
-          git config --global user.email '${{ steps.user-id.outputs.user-id }}+${{ steps.app-token.outputs.app-slug }}[bot]@users.noreply.github.com'
+          git config --global user.name "$name"
+          git config --global user.email "$email"
 
       - name: Checkout repository
         uses: actions/checkout@v4