Fix bug with dates

https://trep.de.dariah.eu/1.0/oaipmh/oai?verb=GetRecord&metadataPrefix=oai_dc&identifier=21.T11991/0000-0011-B8C6-E

java.time.format.DateTimeParseException: Text '2018-10-16T17:39:55.222' could not be parsed at index 23
	java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
	java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
	java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
	java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
	info.textgrid.middleware.OaipmhUtilities.getUTCDateAsString(OaipmhUtilities.java:148)
	info.textgrid.middleware.RecordDelivererDC.getRecordById(RecordDelivererDC.java:82)
	info.textgrid.middleware.OaipmhImpl.getRecordRequest(OaipmhImpl.java:336)
	info.textgrid.middleware.OaipmhImpl.handleRequest(OaipmhImpl.java:810)
	info.textgrid.middleware.OaipmhImpl.getRequest(OaipmhImpl.java:207)
	sun.reflect.GeneratedMethodAccessor115.invoke(Unknown Source)
	sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	java.lang.reflect.Method.invoke(Method.java:498)
	org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:179)
	org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96)
	org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:201)
	org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:104)
	org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:59)
	org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:96)
	org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308)
	org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
	org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:265)
	org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234)
	org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:208)
	org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:160)
	org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:225)
	org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:304)
	org.apache.cxf.transport.servlet.AbstractHTTPServlet.doGet(AbstractHTTPServlet.java:222)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:279)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)