Bump actions/checkout from 2.3.5 to 2.4.0 (#22)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/lint.yaml

@@ -18,7 +18,7 @@ jobs:
       addons: ${{ steps.addons.outputs.addons_list }}
     steps:
       - name: ⤵️ Check out code from GitHub
-        uses: actions/checkout@v2.3.5
+        uses: actions/checkout@v2.4.0
 
       - name: 🔍 Find add-on directories
         id: addons
@@ -33,7 +33,7 @@ jobs:
         path: ${{ fromJson(needs.find.outputs.addons) }}
     steps:
       - name: ⤵️ Check out code from GitHub
-        uses: actions/checkout@v2.3.5
+        uses: actions/checkout@v2.4.0
 
       - name: 🚀 Run Home Assistant Add-on Lint
         uses: frenck/action-addon-linter@v2.5