chore(.github/workflows): replace set-output commands (#18762)

Following deprecation, c.f. https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/
The check that this change worked ok is that the action produces a correctly named artifact

.github/workflows/bors.yml

@@ -90,7 +90,7 @@ jobs:
         run: |
           set -o pipefail
           leanpkg configure
-          echo "::set-output name=started::true"
+          echo "started=true" >> $GITHUB_OUTPUT
           lean --json -T100000 --make src | python3 scripts/detect_errors.py
           lean --json -T400000 --make src | python3 scripts/detect_errors.py
 
@@ -111,7 +111,7 @@ jobs:
           touch workspace.tar
           tar -cf workspace.tar --exclude=*.tar* .
           git_hash="$(git log -1 --pretty=format:%h)"
-          echo "::set-output name=artifact_name::precompiled-mathlib-$short_lean_version-$git_hash"
+          echo "artifact_name=precompiled-mathlib-$short_lean_version-$git_hash" >> $GITHUB_OUTPUT
 
       - name: upload precompiled mathlib zip file
         if: always() && steps.build.outputs.started == 'true'

.github/workflows/build.yml

@@ -98,7 +98,7 @@ jobs:
         run: |
           set -o pipefail
           leanpkg configure
-          echo "::set-output name=started::true"
+          echo "started=true" >> $GITHUB_OUTPUT
           lean --json -T100000 --make src | python3 scripts/detect_errors.py
           lean --json -T400000 --make src | python3 scripts/detect_errors.py
 
@@ -119,7 +119,7 @@ jobs:
           touch workspace.tar
           tar -cf workspace.tar --exclude=*.tar* .
           git_hash="$(git log -1 --pretty=format:%h)"
-          echo "::set-output name=artifact_name::precompiled-mathlib-$short_lean_version-$git_hash"
+          echo "artifact_name=precompiled-mathlib-$short_lean_version-$git_hash" >> $GITHUB_OUTPUT
 
       - name: upload precompiled mathlib zip file
         if: always() && steps.build.outputs.started == 'true'

.github/workflows/build.yml.in

@@ -76,7 +76,7 @@ jobs:
         run: |
           set -o pipefail
           leanpkg configure
-          echo "::set-output name=started::true"
+          echo "started=true" >> $GITHUB_OUTPUT
           lean --json -T100000 --make src | python3 scripts/detect_errors.py
           lean --json -T400000 --make src | python3 scripts/detect_errors.py
 
@@ -97,7 +97,7 @@ jobs:
           touch workspace.tar
           tar -cf workspace.tar --exclude=*.tar* .
           git_hash="$(git log -1 --pretty=format:%h)"
-          echo "::set-output name=artifact_name::precompiled-mathlib-$short_lean_version-$git_hash"
+          echo "artifact_name=precompiled-mathlib-$short_lean_version-$git_hash" >> $GITHUB_OUTPUT
 
       - name: upload precompiled mathlib zip file
         if: always() && steps.build.outputs.started == 'true'

.github/workflows/build_fork.yml

@@ -96,7 +96,7 @@ jobs:
         run: |
           set -o pipefail
           leanpkg configure
-          echo "::set-output name=started::true"
+          echo "started=true" >> $GITHUB_OUTPUT
           lean --json -T100000 --make src | python3 scripts/detect_errors.py
           lean --json -T400000 --make src | python3 scripts/detect_errors.py
 
@@ -117,7 +117,7 @@ jobs:
           touch workspace.tar
           tar -cf workspace.tar --exclude=*.tar* .
           git_hash="$(git log -1 --pretty=format:%h)"
-          echo "::set-output name=artifact_name::precompiled-mathlib-$short_lean_version-$git_hash"
+          echo "artifact_name=precompiled-mathlib-$short_lean_version-$git_hash" >> $GITHUB_OUTPUT
 
       - name: upload precompiled mathlib zip file
         if: always() && steps.build.outputs.started == 'true'