Bump xstream from 1.4.16 to 1.4.18 in /apiconnector#51

dependabot[bot] wants to merge 1 commit intomasteropenml/openml-java:masterfrom

dependabot/maven/apiconnector/com.thoughtworks.xstream-xstream-1.4.18openml/openml-java:dependabot/maven/apiconnector/com.thoughtworks.xstream-xstream-1.4.18Copy head branch name to clipboard