Fix shellcheck url (#6462)

.gitlab-ci/shellcheck.yml

@@ -7,7 +7,7 @@ shellcheck:
     SHELLCHECK_VERSION: v0.6.0
   before_script:
     - ./tests/scripts/rebase.sh
-    - curl --silent "https://storage.googleapis.com/shellcheck/shellcheck-"${SHELLCHECK_VERSION}".linux.x86_64.tar.xz" | tar -xJv
+    - curl --silent --location "https://github.com/koalaman/shellcheck/releases/download/"${SHELLCHECK_VERSION}"/shellcheck-"${SHELLCHECK_VERSION}".linux.x86_64.tar.xz" | tar -xJv
     - cp shellcheck-"${SHELLCHECK_VERSION}"/shellcheck /usr/bin/
     - shellcheck --version
   script: