Use HTTPS for Maven repository access

pom.xml

diff --git a/pom.xml b/pom.xml
index 319005e..b7086e7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -543,7 +543,7 @@
         <pluginRepository>
             <id>apache.snapshots</id>
             <name>Apache Snapshot Repository</name>
-            <url>http://repository.apache.org/snapshots</url>
+            <url>https://repository.apache.org/snapshots</url>
             <snapshots>
                 <enabled>true</enabled>
                 <updatePolicy>daily</updatePolicy>