Update links to search.maven.org

This site has undergone a major rework and the
old links don't work anymore

Author: felixbarny

README.md

@@ -1,6 +1,6 @@
 [![Build Status](https://apm-ci.elastic.co/job/elastic+apm-agent-java+master/badge/icon)](https://apm-ci.elastic.co/job/elastic+apm-agent-java+master/)
 [![codecov](https://codecov.io/gh/elastic/apm-agent-java/branch/master/graph/badge.svg)](https://codecov.io/gh/elastic/apm-agent-java)
-[![Maven Central](https://img.shields.io/maven-central/v/co.elastic.apm/apm-agent-api.svg)](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22co.elastic.apm%22%20AND%20a%3A%22apm-agent-api%22)
+[![Maven Central](https://img.shields.io/maven-central/v/co.elastic.apm/apm-agent-api.svg)](https://search.maven.org/search?q=g:co.elastic.apm%20AND%20a:elastic-apm-agent)
 
 # apm-agent-java
 

docs/intro.asciidoc

@@ -33,7 +33,7 @@ Please also have a look at the documentation for
 === Get started
 
 The first step in getting started with the Elastic APM Java agent ist to download the latest release of the agent jar file from
-link:http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22co.elastic.apm%22%20AND%20a%3A%22elastic-apm-agent%22[maven central].
+link:https://search.maven.org/search?q=g:co.elastic.apm%20AND%20a:elastic-apm-agent[maven central].
 
 NOTE: Don't declare a dependency to the agent in your application.
 

docs/opentracing.asciidoc

@@ -56,7 +56,7 @@ compile "co.elastic.apm:apm-opentracing:$elasticApmVersion"
 ----
 
 Replace the version placeholders with the
-link:http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22co.elastic.apm%22%20AND%20a%3A%22apm-opentracing%22[
+link:https://search.maven.org/search?q=g:co.elastic.apm%20AND%20a:apm-opentracing[
 latest version from maven central]:
 image:https://img.shields.io/maven-central/v/co.elastic.apm/apm-opentracing.svg[Maven Central]
 

docs/public-api.asciidoc

@@ -28,7 +28,7 @@ compile "co.elastic.apm:apm-agent-api:$elasticApmVersion"
 ----
 
 Replace the version placeholders with the
-link:http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22co.elastic.apm%22%20AND%20a%3A%22apm-agent-api%22[
+link:https://search.maven.org/search?q=g:co.elastic.apm%20AND%20a:apm-agent-api[
 latest version from maven central]:
 image:https://img.shields.io/maven-central/v/co.elastic.apm/apm-agent-api.svg[Maven Central]