[Java] Retrofit2 Play! Framework 2.6.x support

[lukoyanov]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: master, 3.3.x, 4.0.x. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

Added Play! Framework 2.6.x support for retrofit2 clients

@bbdouglas (2017/07) @JFCote (2017/08) @sreeshas (2017/08) @jfiala (2017/08) @cbornet (2017/09) @jeff9finger (2018/01)

[wing328]

@lukoyanov thanks for the PR. Some sample files were not up-to-date:

# START SCRIPT: ./bin/utils/ensure-up-to-date
IMPORTANT: this script should be run by the CI (e.g. Shippable) to ensure that the 'samples/' folder is up to date.
Please press CTRL+C to stop or the script will continue in 5 seconds.
UNCOMMITTED CHANGES ERROR
There are uncommitted changes in working tree after execution of 'bin/ensure-up-to-date'
Perform git diff
diff --git a/samples/client/petstore/java/retrofit2-play24/pom.xml b/samples/client/petstore/java/retrofit2-play24/pom.xml
index 305b7e5e3..0ebc80926 100644
--- a/samples/client/petstore/java/retrofit2-play24/pom.xml
+++ b/samples/client/petstore/java/retrofit2-play24/pom.xml
@@ -251,6 +251,7 @@
                 <artifactId>jackson-datatype-jsr310</artifactId>
                 <version>${jackson-version}</version>
             </dependency>
+
             <dependency>
                 <groupId>com.typesafe.play</groupId>
                 <artifactId>play-java-ws_2.11</artifactId>
@@ -258,6 +259,7 @@
             </dependency>
 
 
+
         <!-- test dependencies -->
         <dependency>
             <groupId>junit</groupId>
diff --git a/samples/client/petstore/java/retrofit2-play25/pom.xml b/samples/client/petstore/java/retrofit2-play25/pom.xml
index 9181b7d41..e26afdebc 100644
--- a/samples/client/petstore/java/retrofit2-play25/pom.xml
+++ b/samples/client/petstore/java/retrofit2-play25/pom.xml
@@ -256,6 +256,7 @@
                 <artifactId>jackson-datatype-jsr310</artifactId>
                 <version>${jackson-version}</version>
             </dependency>
+
             <dependency>
                 <groupId>com.typesafe.play</groupId>
                 <artifactId>play-java-ws_2.11</artifactId>
@@ -263,6 +264,7 @@
             </dependency>
 
 
+
         <!-- test dependencies -->
         <dependency>
             <groupId>junit</groupId>
Perform git status
HEAD detached at FETCH_HEAD
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   samples/client/petstore/java/retrofit2-play24/pom.xml
	modified:   samples/client/petstore/java/retrofit2-play25/pom.xml

Please update them so that the CI build can pass.

[wing328]

@lukoyanov can you please also update the CircleCI's pom under the CI folder to test samples/client/petstore/java/retrofit2-play26?

https://github.com/OpenAPITools/openapi-generator/blob/master/CI/pom.xml.circleci#L901

[wing328]

LGTM

[wing328]

@lukoyanov thanks for the PR, which has been included in the v3.2.3 release: https://twitter.com/oas_generator/status/1035200785066254336