describe Shields.io usage

fixes #171

Author: hboutemy

src/main/java/org/apache/maven/plugins/artifact/buildinfo/ReproducibleCentralReport.java

@@ -94,8 +94,20 @@ protected void executeReport(Locale locale) throws MavenReportException {
         sink.link("https://github.com/jvm-repo-rebuild/reproducible-central");
         sink.text("Reproducible Central");
         sink.link_();
-        sink.text(" data.");
-        sink.text("If you think data is not accurate, please help improve.");
+        sink.text(" data rendered as ");
+        sink.link("https://shields.io/");
+        sink.figureGraphics("https://img.shields.io/badge/.-.-green");
+        sink.text("Shields.io");
+        sink.link_();
+        sink.text(" ");
+        sink.link("https://shields.io/badges/reproducible-central-artifact");
+        sink.text("Reproducible Central Artifact");
+        sink.link_();
+        sink.text(" badges. If you think data is not accurate, please ");
+        sink.link("https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/doc/TOOLS.md");
+        sink.text("help us");
+        sink.link_();
+        sink.text(" improve.");
         sink.paragraph_();
         sink.section1_();
         sink.body_();