fix: add environment variable for .NET installation directory in deploy workflow

.gitea/workflows/deploy.yml

@@ -8,6 +8,8 @@ on:
 jobs:
   deploy:
     runs-on: website-deploy-runner
+    env:
+      DOTNET_INSTALL_DIR: "$HOME/.dotnet"
 
     steps:
       - name: Checkout Code
@@ -17,6 +19,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: '8.0.x'
+          cache: true
 
       - name: Create Backend appsettings.Production.json
         run: |