build: use correct secret name in merge_ready_prs workflow

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: na
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: passed
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: Planeshifter

.github/workflows/merge_ready_prs.yml

@@ -50,8 +50,8 @@ jobs:
       # Merge PRs with Ready to Merge label:
       - name: 'Merge PRs'
         env:
-          GH_TOKEN: ${{ secrets.STDLIB_BOT_GITHUB_TOKEN }}
-          GITHUB_TOKEN: ${{ secrets.STDLIB_BOT_GITHUB_TOKEN }}
+          GH_TOKEN: ${{ secrets.STDLIB_BOT_PAT_REPO_WRITE }}
+          GITHUB_TOKEN: ${{ secrets.STDLIB_BOT_PAT_REPO_WRITE }}
         run: |
           # Get all PRs with the "Ready to Merge" label:
           prs=$(gh pr list --label "Ready to Merge" --json number --jq '.[].number')