.github: Upgrade checkout action version

Author: df7cb

.github/workflows/regression.yml

@@ -13,22 +13,22 @@ jobs:
     strategy:
       matrix:
         pgversion:
-          - 9.5
-          - 9.6
-          - 10
-          - 11
-          - 12
-          - 13
-          - 14
-          - 15
           - 16
+          - 15
+          - 14
+          - 13
+          - 12
+          - 11
+          - 10
+          - 9.6
+          - 9.5
 
     env:
       PGVERSION: ${{ matrix.pgversion }}
 
     steps:
     - name: checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: install pg
       run: |