Upgrade to SI-tools version 0.3.1

This patch fixes a critical bug that would strip away all specified tags
instead of only the tags if a pinned version exists.

.gitlab-ci.yml

@@ -8,7 +8,7 @@ stages:
 
 variables:
   CI_REGISTRY_IMAGE_VERSION: "1.2.0"
-  CI_REGISTRY_BUILD_ARG: "--build-arg SI_TOOLS_VERSION=0.3.0"
+  CI_REGISTRY_BUILD_ARG: "--build-arg SI_TOOLS_VERSION=0.3.1"
 
 
 container-test: