fix: allow build steps to access timezone (#28510)

## Problem

The deprecated attribute linter was failing with timezone database errors:
```
unable to locate share/zoneinfo in the local timezone database at /etc/localtime
```

This was happening because the linter uses `Std.Time.PlainDate.now` to compare dates, which requires timezone information.

## Solution

Add `-ro /etc/timezone` to `landrun` shell options.

## Changes

- Add timezone permissions to `shell` in `.github/build.in.yml`
- Regenerated all build workflow files (`build.yml`, `bors.yml`, `build_fork.yml`)

This should fix the deprecated attribute linter failures in CI.

Co-authored-by: Kim Morrison <477956+kim-em@users.noreply.github.com>
Co-authored-by: Bryan Gin-ge Chen <bryangingechen@gmail.com>

Author: kim-em

.github/build.in.yml

@@ -43,7 +43,7 @@ jobs:
       test-outcome: ${{ steps.test.outcome }}
     defaults: # On Hoskinson runners, landrun is already installed.
       run:
-        shell: landrun --rox /usr --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
+        shell: landrun --rox /usr --ro /etc/timezone --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
     steps:
       - name: cleanup
         shell: bash    # This *just* deletes old files, so is safe to run outside landrun.

.github/workflows/bors.yml

@@ -53,7 +53,7 @@ jobs:
       test-outcome: ${{ steps.test.outcome }}
     defaults: # On Hoskinson runners, landrun is already installed.
       run:
-        shell: landrun --rox /usr --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
+        shell: landrun --rox /usr --ro /etc/timezone --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
     steps:
       - name: cleanup
         shell: bash    # This *just* deletes old files, so is safe to run outside landrun.

.github/workflows/build.yml

@@ -60,7 +60,7 @@ jobs:
       test-outcome: ${{ steps.test.outcome }}
     defaults: # On Hoskinson runners, landrun is already installed.
       run:
-        shell: landrun --rox /usr --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
+        shell: landrun --rox /usr --ro /etc/timezone --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
     steps:
       - name: cleanup
         shell: bash    # This *just* deletes old files, so is safe to run outside landrun.

.github/workflows/build_fork.yml

@@ -57,7 +57,7 @@ jobs:
       test-outcome: ${{ steps.test.outcome }}
     defaults: # On Hoskinson runners, landrun is already installed.
       run:
-        shell: landrun --rox /usr --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
+        shell: landrun --rox /usr --ro /etc/timezone --rw /dev --rox /home/lean/.elan --rox /home/lean/actions-runner/_work --rox /home/lean/.cache/mathlib/ --rw pr-branch/.lake/ --env PATH --env HOME --env GITHUB_OUTPUT -- bash -euxo pipefail {0}
     steps:
       - name: cleanup
         shell: bash    # This *just* deletes old files, so is safe to run outside landrun.