Add variable for the metrics api host

Author: jdgwartney

pom.xml

@@ -5,7 +5,7 @@
   <groupId>com.boundary</groupId>
   <artifactId>boundary-plugin-postgresql</artifactId>
   <packaging>jar</packaging>
-  <version>01.00.00</version>
+  <version>1.0.0</version>
   <name>boundary_plugin_postgresql</name>
   <description>Boundary Plugin PostgreSQL extracts metrics from a PostgreSQL database instance.</description>
   <url>https://github.com/boundary/boundary-plugin-postgresql</url>
@@ -32,7 +32,7 @@
                <argument>PUT</argument>
                <argument>-u</argument>
                <argument>${boundary-metrics-user}:${boundary-metrics-password}</argument>
-               <argument>https://premium-api.boundary.com/v1/plugins/private/${project.name}/boundary/${project.artifactId}</argument>
+               <argument>https://${boundary-metrics-api-host}/v1/plugins/private/${project.name}/boundary/${project.artifactId}</argument>
              </arguments>
            </configuration>
          </execution>