Bump actions/download-artifact from v1 to v2

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from v1 to v2.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v1...1de1dea)

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

.github/workflows/ci.yml

@@ -99,11 +99,11 @@ jobs:
     steps:
       - uses: actions/checkout@v2.3.1
       - name: Download result for test execution
-        uses: actions/download-artifact@v1
+        uses: actions/download-artifact@v2
         with:
           name: jacoco
       - name: Download test coverage result for integration and system test execution
-        uses: actions/download-artifact@v1
+        uses: actions/download-artifact@v2
         with:
           name: jacoco-it
       - uses: actions/cache@v2