fix format of local parameters

Author: tomix26

src/main/java/io/zonky/test/db/postgres/embedded/EmbeddedPostgres.java

@@ -289,8 +289,7 @@ private List<String> createLocaleOptions()
     {
         final List<String> localeOptions = new ArrayList<>();
         for (final Entry<String, String> config : localeConfig.entrySet()) {
-          localeOptions.add("--" + config.getKey());
-          localeOptions.add(config.getValue());
+            localeOptions.add(String.format("--%s=%s", config.getKey(), config.getValue()));
         }
         return localeOptions;
     }