Specify path to Oxygen Maven repository in pom.xml

[raducoravu]

Feedback from one of our customers:

I could not get the pom file to work at this location dim-master/oxygen-sdk-workspace/sdkExtensions/pom.xml. I had to add this:

<repositories>
  <repository>
    <id>oxygenxml</id>
    <name>oXygen XML SDK Maven Repository</name>
    <url>https://oxygenxml.com/maven/</url>
  </repository>
</repositories>

before I could build it properly.