CI: Setup dotnet SDK before running automatic build

.gitea/workflows/ci.yml

@@ -13,6 +13,8 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
+    - name: Setup Dotnet SDK
+      uses: https://github.com/actions/setup-dotnet@v4
     - name: Checkout
       uses: https://github.com/actions/checkout@v4
     - name: Build

.gitea/workflows/release.yml

@@ -19,6 +19,8 @@ jobs:
         git branch --remote --contains | grep origin/main
     - name: Set VERSION variable from tag
       run: echo "VERSION=${GITEA_REF/refs\/tags\/v/}" >> $GITEA_ENV
+    - name: Setup Dotnet SDK
+      uses: https://github.com/actions/setup-dotnet@v4
     - name: Build
       run: dotnet build --configuration Release /p:Version=${VERSION}
     - name: Test