Ran into a similar issue today. In my case, it was the shade plugin that was the culprit, in addition to springframework.org having an outage. The following snippet cleared things up:
<transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
<resource>META-INF/spring.schemas</resource>
</transformer>
<transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
<resource>META-INF/spring.handlers</resource>
</transformer>
HTH someone