Auto merge of #71675 - pietroalbini:ci-fix-shrink-regression, r=Mark-Simulacrum

ci: use bash when executing the "bors build finished" jobs

We don't clone the repository in those builders, so the default shell (`src/ci/exec-with-shell.py`) is not present there. This fixes a GHA regression introduced in #71434.

r? @Mark-Simulacrum

src/ci/github-actions/ci.yml

@@ -210,12 +210,14 @@ x--expand-yaml-anchors--remove:
     steps:
       - name: mark the job as a success
         run: exit 0
+        shell: bash
     <<: *base-outcome-job
 
   - &base-failure-job
     steps:
       - name: mark the job as a failure
         run: exit 1
+        shell: bash
     <<: *base-outcome-job
 
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