Update benchmark-action.yml to use NET 8 (#5157)

* Update benchmark-action.yml

* Update actions/cache to version 3 in workflow

Author: gladjohn

.github/workflows/benchmark-action.yml

@@ -26,12 +26,12 @@ jobs:
       - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
       - uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '6.0.418'
+          dotnet-version: '8.0.x'
       - name: Run benchmark
-        run: cd tests/Microsoft.Identity.Test.Performance && dotnet run -c release -f net6.0 --exporters json 
+        run: cd tests/Microsoft.Identity.Test.Performance && dotnet run -c release -f net8.0 --exporters json 
 
       - name: Download previous benchmark data
-        uses: actions/cache@e12d46a63a90f2fae62d114769bbf2a179198b5c # v3.3.3
+        uses: actions/cache@v3
         with:
           path: ./cache
           key: ${{ runner.os }}-benchmark