github: Use checkout@v3 (#3700)

.github/workflows/build.yml

@@ -61,7 +61,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       with:
         path: repo
 

.github/workflows/contributor.yml

@@ -13,5 +13,5 @@ jobs:
     name: "'docs/CONTRIBUTORS' was signed"
     runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - run: test_regress/t/t_dist_contributors.pl

.github/workflows/coverage.yml

@@ -31,7 +31,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       with:
         path: repo
 

.github/workflows/format.yml

@@ -19,7 +19,7 @@ jobs:
       CI_M32: 0
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
       - name: Install packages for build