Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/publish.yml

@@ -8,7 +8,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v2
         with:
             node-version: 14
@@ -19,7 +19,7 @@ jobs:
     needs: test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v2
         with:
           node-version: 14
@@ -33,7 +33,7 @@ jobs:
     needs: test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v2
         with:
           node-version: 14

.github/workflows/testing.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: install
         run: npm ci