Update actions/checkout action to v3 (#425)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions/setup-node@v2
         with:
           node-version: "10"
@@ -45,7 +45,7 @@ jobs:
 
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions/setup-node@v2
         with:
           node-version: 10
@@ -63,7 +63,7 @@ jobs:
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions/setup-node@v2
         with:
           node-version: "14"