Tox error occures in master branch because lacking of required properties

As of 3/10, when I cloned the master branch of Heat-translator and executed tox, I got errors in some testcases.
This is a critical issue and all patches can not be merged.
The details of the error are as follows.

```
$ tox -e py38
...snip...
FAIL: translator.tests.test_tosca_hot_translation.ToscaHotTranslationTest.test_hot_translate_nfv_scaling_with_params
tags: worker-1
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/heat-translator/translator/tests/test_tosca_hot_translation.py", line 606, in test_hot_translate_nfv_scaling_with_params
    self._test_successful_translation(tosca_file, hot_files, params)
  File "/tmp/heat-translator/translator/tests/test_tosca_hot_translation.py", line 34, in _test_successful_translation
    diff = TranslationUtils.compare_tosca_translation_with_hot(tosca_file,
  File "/tmp/heat-translator/translator/common/utils.py", line 244, in compare_tosca_translation_with_hot
    tosca = ToscaTemplate(tosca_tpl, params, a_file)
  File "/tmp/heat-translator/.tox/py38/lib/python3.8/site-packages/toscaparser/tosca_template.py", line 115, in __init__
    self.verify_template()
  File "/tmp/heat-translator/.tox/py38/lib/python3.8/site-packages/toscaparser/tosca_template.py", line 303, in verify_template
    raise ValidationError(
toscaparser.common.exception.ValidationError:
The input "/tmp/heat-translator/translator/tests/data/nfv/test_tosca_nfv_autoscaling_with_params.yaml" failed validation with the following error(s):

        MissingRequiredFieldError: "properties" of template "SP" is missing required field "['targets']".
...snip...
```

This is because the version of tosca-parser that reflects the following 'validation for required property of policies' has been released and is now installed when tox is executed.
https://opendev.org/openstack/tosca-parser/commit/00d3a394d5a3bc13ed7d2f1d71affd9ab71e4318

The bug report of tosca-parser is as follows.
https://bugs.launchpad.net/tosca-parser/+bug/1903233

In the unittest of Heat-translator, the errors occur because there are testcases and yaml that violate 'required property of policies'.