ci: fix pullreq number may not get correctly (#12127)

* Revert "remove save-pr-number"

This reverts commit 085f4bd769.

* Revert "Update report-api-diff.yml"

This reverts commit b73daf4c0e.

* Revert "Update report-api-diff.yml"

This reverts commit cbf2b5ad8a.

* Revert "try to get pull request id from github.event.workflow_run.pull_requests"

This reverts commit 07517ce501.

.github/workflows/get-api-diff.yml

@@ -171,3 +171,16 @@ jobs:
         path: api-head.json
     - name: Kill Misskey Job
       run: screen -S misskey -X quit
+
+  save-pr-number:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Save PR number
+        env:
+          PR_NUMBER: ${{ github.event.number }}
+        run: |
+          echo "$PR_NUMBER" > ./pr_number
+      - uses: actions/upload-artifact@v3
+        with:
+          name: api-artifact
+          path: pr_number

.github/workflows/report-api-diff.yml

@@ -39,14 +39,7 @@ jobs:
         run: unzip api-artifact.zip -d artifacts
       - name: Load PR Number
         id: load-pr-num
-        env:
-          PULL_REQUESTS: ${{ toJson(github.event.workflow_run.pull_requests.*) }}
-          REPO_ID: ${{ github.repository_id }}
-        run: |
-          # find first pull requests that targets this repository
-          PR_NUMBER="$(echo "$PULL_REQUESTS" \
-              | jq --arg REPO_ID "$REPO_ID" '[.[] | select ($REPO_ID == (.base.repo.id | tostring)) | .number ][0]')"
-          echo "pr-number=$PR_NUMBER" >> "$GITHUB_OUTPUT"
+        run: echo "pr-number=$(cat artifacts/pr_number)" >> "$GITHUB_OUTPUT"
 
       - name: Output base
         run: cat ./artifacts/api-base.json