Upgraded HttpCore to version 5.1
diff --git a/pom.xml b/pom.xml
index 5e1c10b..fc870d0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -62,7 +62,7 @@
   <properties>
     <maven.compiler.source>1.7</maven.compiler.source>
     <maven.compiler.target>1.7</maven.compiler.target>
-    <httpcore.version>5.1-beta3</httpcore.version>
+    <httpcore.version>5.1</httpcore.version>
     <log4j.version>2.9.1</log4j.version>
     <commons-codec.version>1.13</commons-codec.version>
     <conscrypt.version>2.2.1</conscrypt.version>