Info about downloading the dependency (#12)

* doc: info about downloading the dependency

Author: lothar1998

README.md

@@ -3,6 +3,20 @@ A gRPC name resolver that uses a Kubernetes API to discover backend servers via
 only the JSON parsing library as the dependency to do not blow your dependency tree.
 
 ### Usage
+#### Maven
+```xml
+<dependency>
+    <groupId>io.github.lothar1998</groupId>
+    <artifactId>kuberesolver-java</artifactId>
+    <version>0.0.1</version>
+</dependency>
+```
+
+#### Gradle
+```groovy
+implementation 'io.github.lothar1998:kuberesolver-java:0.0.1'
+```
+Then register `KubernetesNameResolverProvider` in default registry:
 ```java
 import io.github.lothar1998.kuberesolver.KubernetesNameResolverProvider;
 import io.grpc.ManagedChannelBuilder;