ci: downgrade actions/cache to v3 to fix pwsh path issue on gitea-act runner

.gitea/workflows/ci.yml

@@ -33,7 +33,7 @@ jobs:
 
       - name: Cache NuGet packages
         id: nuget-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         continue-on-error: true
         with:
           path: ${{ runner.temp }}/.nuget/packages
@@ -77,7 +77,7 @@ jobs:
 
       - name: Cache NuGet packages
         id: nuget-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         continue-on-error: true
         with:
           path: ${{ runner.temp }}/.nuget/packages
@@ -130,7 +130,7 @@ jobs:
 
       - name: Cache NuGet packages
         id: nuget-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         continue-on-error: true
         with:
           path: ${{ runner.temp }}/.nuget/packages