feat: use download-artifact instead of manually downloading it

This should hopefully work on private repos too!

action.yml

@@ -39,6 +39,8 @@ inputs:
   artifact-name:
     description: The name of the generated artifact.
     default: report.json
+  github-token:
+    description: A github token with read permissions for this repository, required if do-comparison is 'true'
   # Comparison Report (comment only)
   do-comparison:
     description: |
@@ -113,7 +115,7 @@ runs:
     - name: Find previous run on base-branch
       # Only run when doing comparisons
       if: inputs.do-comparison == 'true'
-      id: previous_report
+      id: previous-report
       continue-on-error: true
       env:
         BASE_BRANCH: ${{ inputs.base-branch }}
@@ -139,15 +141,15 @@ runs:
             --arg head_branch "${BASE_BRANCH:-$(default_branch)}" \
             '[.workflow_runs[] | select(.name == $name and .head_branch == $head_branch)] | first | .id')
 
-        echo "run_id=$run_id" >> "$GITHUB_OUTPUT"
+        echo "run-id=$run_id" >> "$GITHUB_OUTPUT"
     - name: Download previous report
-      uses: https://git.salame.cl/actions/download-artifact@v4
+      uses: https://git.salame.cl/actions/download-artifact@d8d0a99033603453ad2255e58720b460a0555e1e # v4
       # Ensure the previous step succeeded
       if: inputs.do-comparison == 'true' && steps.previous_report.outcome == 'success'
       with:
         name: ${{ inputs.artifact-name }}
-        github-token: ${{ github.token }}
-        run-id: ${{ steps.previous_report.run_id }}
+        github-token: ${{ inputs.github-token }}
+        run-id: ${{ steps.previous-report.run-id }}
     - name: Create report
       if: inputs.comment-on-pr == 'true' || inputs.generate-artifact == 'true'
       env: