[#1578] Change Sonatype URL in README.md (#1597)

fixes #1578

README.md

@@ -83,7 +83,7 @@ Latest weekly build (additional repository is required):
 <repositories>
     <repository>
         <id>oss.sonatype.org-snapshot</id>
-        <url>http://oss.sonatype.org/content/repositories/snapshots</url>
+        <url>https://oss.sonatype.org/content/repositories/snapshots</url>
         <releases><enabled>false</enabled></releases>
         <snapshots><enabled>true</enabled></snapshots>
     </repository>