Pre release updates (#66)

* Update duracloud and duracloud-db to 8.0.0

* Update nexus staging plugin

pom.xml

@@ -172,8 +172,8 @@
     <log.level.default>INFO</log.level.default>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-    <duracloud.version>7.2.0-SNAPSHOT</duracloud.version>
-    <duracloud.db.version>7.2.0-SNAPSHOT</duracloud.db.version>
+    <duracloud.version>8.0.0</duracloud.version>
+    <duracloud.db.version>8.0.0</duracloud.db.version>
     <duraspace-codestyle.version>1.1.0</duraspace-codestyle.version>
     <aws.sdk.version>1.12.548</aws.sdk.version>
     <spring.framework.version>5.3.29</spring.framework.version>
@@ -302,7 +302,7 @@
       <plugin>
         <groupId>org.sonatype.plugins</groupId>
         <artifactId>nexus-staging-maven-plugin</artifactId>
-        <version>1.6.6</version>
+        <version>1.6.13</version>
         <extensions>true</extensions>
         <configuration>
           <serverId>sonatype-releases</serverId>