Update actions/cache action to v6

Author: renovate[bot]

.github/workflows/main.yml

@@ -39,7 +39,7 @@ jobs:
       - if: runner.os != 'macOS' # TODO[#430]: Re-enable this back after https://github.com/actions/runner-images/issues/13341
                                  #             is resolved.
         name: NuGet cache
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ${{ env.NUGET_PACKAGES }}
           key: ${{ runner.os }}.nuget.${{ hashFiles('**/*.*proj') }}

.github/workflows/release.yml

@@ -46,7 +46,7 @@ jobs:
         uses: actions/setup-dotnet@v5
 
       - name: NuGet cache
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ${{ env.NUGET_PACKAGES }}
           key: ${{ runner.os }}.nuget.${{ hashFiles('**/*.*proj') }}