build(deps): bump the gha-dependencies group with 2 updates

Bumps the gha-dependencies group with 2 updates: [actions/upload-artifact](https://github.com/actions/upload-artifact) and [actions/download-artifact](https://github.com/actions/download-artifact).


Updates `actions/upload-artifact` from 6 to 7
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

Updates `actions/download-artifact` from 7 to 8
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: gha-dependencies
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: gha-dependencies
...

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

Author: dependabot[bot]

.github/workflows/merge_to_main.yml

@@ -32,7 +32,7 @@ jobs:
         run: make build
         shell: bash
       - name: "Upload Build"
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: fastly-cli-build-${{ matrix.platform }}-${{ github.sha }}
           path: fastly

.github/workflows/pr_test.yml

@@ -30,7 +30,7 @@ jobs:
       - name: "Generate static app config"
         run: make config
       - name: "Config Artifact"
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: config-artifact-${{ github.sha }}
           path: pkg/config/config.toml
@@ -50,7 +50,7 @@ jobs:
         run: make mod-download
         shell: bash
       - name: "Config Artifact"
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: config-artifact-${{ github.sha }}
       - name: "Move Config"
@@ -93,7 +93,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
       - name: "Config Artifact"
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: config-artifact-${{ github.sha }}
       - name: "Move Config"
@@ -136,7 +136,7 @@ jobs:
         with:
           fetch-depth: 0
       - name: Download config artifact
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: config-artifact-${{ github.sha }}
           path: pkg/config