[BUG] python-flask controller test uses true instead of True

Boolean values get parsed badly in flask.

openapi: 3.0.0
info:
  title: Bar
  description: Foo
  version: 0.1.0
paths:
  /foo:
    post:
      summary: Bar
      description: desc
      requestBody:
        description: Optional description in *Markdown*
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ScenarioParameters'
      responses:
        '200':    # status code
          description: A JSON object containing the result data
          content:
            application/json:
              schema: 
                type: string

components: 
  schemas:
    ScenarioParameters:
      type: object
      properties:
        foo:
          type: boolean

leads to

class TestDefaultController(BaseTestCase):
    """DefaultController integration test stubs"""

    def test_foo_post(self):
        """Test case for foo_post

        Bar
        """
        scenario_parameters = {
  "foo" : true
}
        headers = { 
            'Accept': 'application/json',
            'Content-Type': 'application/json',
        }
        response = self.client.open(
            '/foo',
            method='POST',
            headers=headers,
            data=json.dumps(scenario_parameters),
            content_type='application/json')
        self.assert200(response,
                       'Response body is : ' + response.data.decode('utf-8'))

in the test_default_controller.py. Note the true instead of True

I believe a fix is to wrap this line the {{{example}}} which is a JSON document into a

"""
{{{example}}}
"""

multi line python string and then set data=json.dumps(...) to the value directly

Start with modules/openapi-generator/src/main/resources/python-flask/controller_test.mustache around the linked line, then compare its output with the generated test_default_controller.py shown in the issue. Regenerate a Python Flask controller test and verify that the boolean example is valid Python and the resulting test runs successfully.