Override the default Maven repository when testing against old Maven …

…versions

.. because otherwise it will attempt to use HTTP rather than HTTPS,
which is rejected by `repo1.maven.org` for security reasons.

src/build/test-pom.xml

@@ -10,6 +10,35 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
 
+  <!--
+    Override the default repository so that the old versions of Maven do not use
+    the insecure HTTP URLs.
+  -->
+  <repositories>
+    <repository>
+      <id>central-overridden</id>
+      <name>Maven Central</name>
+      <url>https://repo1.maven.org/maven2/</url>
+      <layout>default</layout>
+      <releases>
+        <enabled>true</enabled>
+        <checksumPolicy>fail</checksumPolicy>
+      </releases>
+    </repository>
+  </repositories>
+  <pluginRepositories>
+    <pluginRepository>
+      <id>central-overridden</id>
+      <name>Maven Central</name>
+      <url>https://repo1.maven.org/maven2/</url>
+      <layout>default</layout>
+      <releases>
+        <enabled>true</enabled>
+        <checksumPolicy>fail</checksumPolicy>
+      </releases>
+    </pluginRepository>
+  </pluginRepositories>
+
   <dependencies>
     <dependency>
       <groupId>io.netty</groupId>