ci: update used github actions to node 20 (#98)

Author: ttu

.github/workflows/ci.yml

@@ -11,8 +11,8 @@ jobs:
  env:
  Solution_name: JsonFlatFileDataStore.sln
  steps:
- - uses: actions/checkout@v3
- - uses: actions/setup-dotnet@v3
+ - uses: actions/checkout@v4
+ - uses: actions/setup-dotnet@v4
  with:
  dotnet-version: |
  6.0.302

.github/workflows/ci_win.yml

@@ -11,8 +11,8 @@ jobs:
  env:
  Solution_name: JsonFlatFileDataStore.sln
  steps:
- - uses: actions/checkout@v3
- - uses: actions/setup-dotnet@v3
+ - uses: actions/checkout@v4
+ - uses: actions/setup-dotnet@v4
  with:
  dotnet-version: |
  6.0.302