Update the versions of cudf and xgboost. (NVIDIA#27)

And remove the internal repo

pom.xml

@@ -13,21 +13,13 @@
 
     <properties>
         <encoding>UTF-8</encoding>
-        <xgboost.version>0.90-SNAPSHOT</xgboost.version>
+        <xgboost.version>0.90-Beta</xgboost.version>
         <spark.version>2.4.0</spark.version>
         <scala.version>2.11.6</scala.version>
         <scala.binary.version>2.11</scala.binary.version>
         <xgbClassifier></xgbClassifier>
     </properties>
 
-    <repositories>
-        <repository>
-            <id>spark.sw.nvidia.com</id>
-            <name>sw-spark-maven</name>
-            <url>https://gpuwa.nvidia.com/artifactory/sw-spark-maven</url>
-        </repository>
-    </repositories>
-
     <dependencies>
         <dependency>
             <groupId>ai.rapids</groupId>
@@ -38,7 +30,7 @@
         <dependency>
             <groupId>ai.rapids</groupId>
             <artifactId>cudf</artifactId>
-            <version>0.8-SNAPSHOT</version>
+            <version>0.8-Beta</version>
             <classifier>${xgbClassifier}</classifier>
         </dependency>
         <dependency>