Bump dawidd6/action-download-artifact from 2 to 6 in /.github/workflows

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2 to 6.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](dawidd6/action-download-artifact@v2...v6)

---
updated-dependencies:
- dependency-name: dawidd6/action-download-artifact
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/cpp-packaging.yml

@@ -654,7 +654,7 @@ jobs:
     if: ${{ github.event.inputs.downloadPublicVersion != '' || github.event.inputs.downloadPreviousRun != '' }}
     steps:
       - name: fetch artifact from previous run
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         if: ${{ github.event.inputs.downloadPreviousRun != '' }}
         with:
           name: 'firebase_cpp_sdk.zip'

.github/workflows/integration_tests.yml

@@ -300,7 +300,7 @@ jobs:
           path: external/vcpkg/installed
           key: dev-vcpkg-${{ env.VCPKG_TRIPLET }}-${{ hashFiles(format('{0}', env.VCPKG_RESPONSE_FILE)) }}-${{ hashFiles('.git/modules/external/vcpkg/HEAD') }}
       - name: Fetch prebuilt packaged SDK from previous run
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         if: ${{ github.event.inputs.test_packaged_sdk != '' }}
         with:
           name: 'firebase_cpp_sdk.zip'
@@ -430,7 +430,7 @@ jobs:
           max_attempts: 3
           command: scripts/gha/install_test_workflow_prereqs.sh -p Android
       - name: Fetch prebuilt packaged SDK from previous run
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         if: ${{ github.event.inputs.test_packaged_sdk != '' }}
         with:
           name: 'firebase_cpp_sdk.zip'
@@ -528,7 +528,7 @@ jobs:
           max_attempts: 3
           command: scripts/gha/install_test_workflow_prereqs.sh -p iOS
       - name: Fetch prebuilt packaged SDK from previous run
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         if: ${{ github.event.inputs.test_packaged_sdk != '' }}
         with:
           name: 'firebase_cpp_sdk.zip'
@@ -627,7 +627,7 @@ jobs:
           max_attempts: 3
           command: scripts/gha/install_test_workflow_prereqs.sh -p tvOS
       - name: Fetch prebuilt packaged SDK from previous run
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         if: ${{ github.event.inputs.test_packaged_sdk != '' }}
         with:
           name: 'firebase_cpp_sdk.zip'