Use HTTPS instead of HTTP to resolve dependencies (#14)

This fixes a security vulnerability in this project where the `pom.xml`
files were configuring Maven to resolve dependencies over HTTP instead of
HTTPS.

Signed-off-by: Jonathan Leitschuh <Jonathan.Leitschuh@gmail.com>
diff --git a/pom.xml b/pom.xml
index 54cf784..4f43924 100644
--- a/pom.xml
+++ b/pom.xml
@@ -332,7 +332,7 @@
   <repositories>
     <repository>
       <id>vysper-custom</id>
-      <url>http://people.apache.org/~ngn/vysper-repo</url>
+      <url>https://people.apache.org/~ngn/vysper-repo</url>
     </repository>
   </repositories>