ci: Use actions/checkout v3

Author: kojix2

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
         - debug
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 1
 
@@ -87,7 +87,7 @@ jobs:
     runs-on: windows-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 1
 
@@ -108,7 +108,7 @@ jobs:
     runs-on: macos-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 1