Bump xstream from 1.4.7 to 1.4.15 in /WebGoat/webgoat-lessons#4

dependabot[bot] wants to merge 1 commit intojposgr-public/test-java:jposfrom

dependabot/maven/WebGoat/webgoat-lessons/com.thoughtworks.xstream-xstream-1.4.15gr-public/test-java:dependabot/maven/WebGoat/webgoat-lessons/com.thoughtworks.xstream-xstream-1.4.15Copy head branch name to clipboard