Initialize optional query parameters with null

Author: agologan

gradle-plugin/plugin/src/main/resources/kotlin/retrofit2/queryParams.mustache

@@ -1 +1 @@
-{{#isQueryParam}}@retrofit2.http.Query("{{baseName}}") {{#collectionFormat}}{{^isCollectionFormatMulti}}@{{{collectionFormat.toUpperCase}}} {{/isCollectionFormatMulti}}{{/collectionFormat}}{{paramName}}: {{{dataType}}}{{/isQueryParam}}
+{{#isQueryParam}}@retrofit2.http.Query("{{baseName}}") {{#collectionFormat}}{{^isCollectionFormatMulti}}@{{{collectionFormat.toUpperCase}}} {{/isCollectionFormatMulti}}{{/collectionFormat}}{{paramName}}: {{{dataType}}}{{^required}} = null{{/required}}{{/isQueryParam}}

samples/junit-tests/src/main/java/com/yelp/codegen/generatecodesamples/apis/ResourceApi.kt

@@ -116,11 +116,11 @@ interface ResourceApi {
     )
     @GET("/symbols/in/parameter/name")
     fun getSymbolsInParameterName(
-        @retrofit2.http.Query("parameter") parameter: String?,
-        @retrofit2.http.Query("brackets[]") brackets: String?,
-        @retrofit2.http.Query("brackets[withText]") bracketsWithText: String?,
-        @retrofit2.http.Query("dot.") dot: String?,
-        @retrofit2.http.Query("dot.withText") dotWithText: String?
+        @retrofit2.http.Query("parameter") parameter: String? = null,
+        @retrofit2.http.Query("brackets[]") brackets: String? = null,
+        @retrofit2.http.Query("brackets[withText]") bracketsWithText: String? = null,
+        @retrofit2.http.Query("dot.") dot: String? = null,
+        @retrofit2.http.Query("dot.withText") dotWithText: String? = null
     ): Completable
     /**
      * The endpoint is owned by junittests service owner