Ensure that HTTP client can authenticate with proxy (#514)

* Ensure that HTTP client can authenticate with proxy

The HTTP client can currently not use proxies which require authentication.
By using a pre-configured base client this error should be mitigated

* Apply Maven spotless plugin

* Update pom.xml according to review comment

Co-authored-by: James Nord <jtnord@users.noreply.github.com>

Co-authored-by: Vanio Begic <vanio.begic@capgemini.com>
Co-authored-by: James Nord <jtnord@users.noreply.github.com>

Author: 3 people

pom.xml

@@ -112,6 +112,10 @@
             <artifactId>workflow-cps-global-lib</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+          <groupId>io.jenkins.plugins</groupId>
+          <artifactId>okhttp-api</artifactId>
+        </dependency>
     </dependencies>
     <dependencyManagement>
         <dependencies>

src/main/java/org/jenkinsci/plugins/github_branch_source/Connector.java

@@ -50,6 +50,7 @@
 import hudson.security.ACL;
 import hudson.util.FormValidation;
 import hudson.util.ListBoxModel;
+import io.jenkins.plugins.okhttp.api.JenkinsOkHttpClient;
 import java.io.File;
 import java.io.IOException;
 import java.net.HttpURLConnection;
@@ -100,7 +101,8 @@ public class Connector {
 
   private static final Random ENTROPY = new Random();
   private static final String SALT = Long.toHexString(ENTROPY.nextLong());
-  private static final OkHttpClient baseClient = new OkHttpClient();
+  private static final OkHttpClient baseClient =
+      JenkinsOkHttpClient.newClientBuilder(new OkHttpClient()).build();
 
   private Connector() {
     throw new IllegalAccessError("Utility class");