fix checkout

.github/workflows/shellcheck.yml

@@ -22,7 +22,7 @@ jobs:
   ShellCheck:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install Shellcheck
       run: sudo apt-get install -y shellcheck
     - name: DoShellcheck
@@ -31,7 +31,7 @@ jobs:
   shfmt:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install shfmt
       run: curl -sSL https://github.com/mvdan/sh/releases/download/v3.1.2/shfmt_v3.1.2_linux_amd64 -o ~/shfmt && chmod +x ~/shfmt
     - name: shfmt