CI: Change actions/checkout version (ScoopInstaller#436)

* (chore): Update bucket files from template

* Remove appveyor.yml

* Remove old test folder and its content

* CI: Change actions/checkout version

Author: se35710

.github/workflows/ci.yml

@@ -11,12 +11,12 @@ jobs:
     runs-on: windows-latest
     steps:
       - name: Checkout Bucket
-        uses: actions/checkout@v2
+        uses: actions/checkout@main
         with:
           fetch-depth: 2
           path: 'my_bucket'
       - name: Checkout Scoop
-        uses: actions/checkout@v2
+        uses: actions/checkout@main
         with:
           repository: ScoopInstaller/Scoop
           path: 'scoop_core'
@@ -31,12 +31,12 @@ jobs:
     runs-on: windows-latest
     steps:
       - name: Checkout Bucket
-        uses: actions/checkout@v2
+        uses: actions/checkout@main
         with:
           fetch-depth: 2
           path: 'my_bucket'
       - name: Checkout Scoop
-        uses: actions/checkout@v2
+        uses: actions/checkout@main
         with:
           repository: ScoopInstaller/Scoop
           path: 'scoop_core'