Merge branch 'mtoff/stable_config' of github.com:DataDog/dd-trace-java into mtoff/stable_config

Author: mtoffl01

Diff for: internal-api/src/main/java/datadog/trace/bootstrap/config/provider/StableConfigSource.java

@@ -59,7 +59,7 @@ public final class StableConfigSource extends ConfigProvider.Source {
   // that way we don't need to call readFromYaml twice;
   // if we see that said cached map is already not null by the name the StableConfigurationSource
   // constructor is called, we can skip calling it again.
-  public static HashMap<String, Object> readYamlFromFile(String filePath) {
+  public static Map<String, Object> readYamlFromFile(String filePath) {
     File file = new File(filePath);
     if (!file.exists()) {
       log.debug(