Require shellwords in artifact rake task (#17319) (#17320)

The #17310 PR changed the rake task for
artifact creation to use shellwords from standard library. The acceptance tests
need to explitily load that library. This commit updates the rake file to handle
loading the required code.

(cherry picked from commit 964468f)

Co-authored-by: Cas Donoghue <[email protected]>

Author: mergify[bot]

rakelib/artifacts.rake

@@ -15,6 +15,8 @@
 # specific language governing permissions and limitations
 # under the License.
 
+require 'shellwords'
+
 namespace "artifact" do
   SNAPSHOT_BUILD = ENV["RELEASE"] != "1"
   VERSION_QUALIFIER = ENV["VERSION_QUALIFIER"].to_s.strip.empty? ? nil : ENV["VERSION_QUALIFIER"]