Adopt central ShellCheck workflow

.github/workflows/ci.yml

@@ -13,17 +13,10 @@ permissions:
 jobs:
   lint:
     name: Lint (shellcheck)
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install shellcheck
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y shellcheck
-      - name: Lint lessons
-        run: shellcheck lessons/*.sh
-      - name: Lint tests
-        run: shellcheck --shell=bash tests/*.bats
+    uses: DevOpsDerek/workflows/.github/workflows/lint-shell.yml@35ec3f531b5eb0f0f42f232f23e1dc5735e36c35
+    with:
+      shellcheck-version: 0.10.0
+      working-directory: .
 
   test:
     name: Test (bats-core)

lint.sh

@@ -6,8 +6,8 @@ if ! command -v shellcheck &>/dev/null; then
   exit 1
 fi
 
-echo "Running shellcheck on lessons/..."
-shellcheck lessons/*.sh
+echo "Running shellcheck on scripts and lessons/..."
+shellcheck ./*.sh lessons/*.sh
 echo "Running shellcheck on tests/..."
 shellcheck --shell=bash tests/*.bats
 echo "All files passed shellcheck."