Bump okhttp from 3.10.0 to 3.12.1 in /core (#1080)

* Bump okhttp from 3.10.0 to 3.12.1 in /core

Bumps [okhttp](https://github.com/square/okhttp) from 3.10.0 to 3.12.1.
- [Release notes](https://github.com/square/okhttp/releases)
- [Changelog](https://github.com/square/okhttp/blob/master/CHANGELOG.md)
- [Commits](square/okhttp@parent-3.10.0...parent-3.12.1)

Signed-off-by: dependabot[bot] <[email protected]>

* Replace OkHttp's internal API usage with public

* exclude `META-INF/proguard/` from the shaded JAR

Author: dependabot[bot]

core/build.gradle

@@ -28,6 +28,7 @@ shadowJar {
         'META-INF/LICENSE.txt',
         'META-INF/DEPENDENCIES',
         'META-INF/maven/',
+        'META-INF/proguard/',
         'META-INF/services/README.md',
         'META-INF/services/com.fasterxml.jackson.core.*',
         'META-INF/services/com.github.dockerjava.api.command.*',
@@ -101,7 +102,7 @@ dependencies {
         exclude(group: 'com.google.code.findbug')
         exclude(group: 'com.kohlschutter.junixsocket')
     }
-    shaded 'com.squareup.okhttp3:okhttp:3.10.0'
+    shaded 'com.squareup.okhttp3:okhttp:3.12.1'
 
     shaded 'org.glassfish.main.external:trilead-ssh2-repackaged:4.1.2'
 

core/src/main/java/org/testcontainers/dockerclient/transport/okhttp/OkHttpDockerCmdExecFactory.java

@@ -14,7 +14,6 @@
 import okhttp3.Dns;
 import okhttp3.HttpUrl;
 import okhttp3.OkHttpClient;
-import okhttp3.internal.Internal;
 import org.apache.commons.io.IOUtils;
 
 import javax.net.ssl.SSLContext;
@@ -98,7 +97,7 @@ public void init(DockerClientConfig dockerClientConfig) {
                     .port(dockerHost.getPort());
                 break;
             default:
-                baseUrlBuilder = Internal.instance.getHttpUrlChecked(dockerHost.toString()).newBuilder();
+                baseUrlBuilder = HttpUrl.get(dockerHost.toString()).newBuilder();
         }
         baseUrl = baseUrlBuilder.build();
     }