ci: Update for net7.0

Author: tuxuser

.github/workflows/dotnetcore.yml

@@ -12,11 +12,11 @@ jobs:
 runs-on: windows-latest
 
 steps:
- - uses: actions/checkout@v2
+ - uses: actions/checkout@v3
  - name: Setup .NET Core
-uses: actions/setup-dotnet@v1
+uses: actions/setup-dotnet@v3
 with:
-dotnet-version: 3.1.101
+dotnet-version: '7.0'
  - name: Install dependencies
 run: dotnet restore
  - name: Build