Missing ServiceLoader entry from META-INF/services

[SorinS]

As the code uses ServiceLoader, a file with the name org.handwerkszeug.dns.conf.NameServerContainer and with the following content:

org.handwerkszeug.dns.conf.DefaultNameServerContainer

should be placed in src/main/resources/META-INF/services - otherwise DNSClient.java will NPE upon container initialization.

[laviua]

#2