##### SUMMARY
If you have executable files in your source code they are not kept in the tarball.

Could be related to https://github.com/ansible/ansible/blob/99d7f150873011e7515851db9b44ff486efa9d77/lib/ansible/galaxy/collection.py#L763

This was noticed as I had some auxiliary scripts in my repo.

Need to also consider scripts in `files/` if/when Collections support roles.

This seems to fail the "principal of least suprise"

**Proposal 1: Keep on stripping executable flags**

Add some line to the output
`WARNING: tests/coverage.sh: source file has executable flag, though this will be ignored in generated tar.gz`
Update developing a collection documentation page
Update integration tests to ensure that executable mode is always stripped.
Update code to link to this issue

**Proposal 2: Allow executible flags**

Update developing a collection documentation page
Update integration tests to ensure that executable mode is preserved
Update code to link to this issue
Changelog


##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ansible-galaxy

##### ANSIBLE VERSION
```paste below
2.10
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can paste gist.github.com links for larger files -->


co.GlobalCLIArgs._Singleton__instance = None
        self.default_args = ['ansible-galaxy']
    def tearDown(self):
        
        co.GlobalCLIArgs._Singleton__instance = None
    def test_init(self):
        galaxy_cli = GalaxyCLI(args=self.default_args)
        self.assertTrue(isinstance(galaxy_cli, GalaxyCLI))
    def test_display_min(self):
        gc = GalaxyCLI(args=self.default_args)
        role_info = {'name': 'some_role_name'}
        display_result = gc._display_role_info(role_info)
        self.assertTrue(display_result.find('some_role_name') > -1)
    def test_display_galaxy_info(self):
        gc = GalaxyCLI(args=self.default_args)
        galaxy_info = {}
        role_info = {'name': 'some_role_name',
                     'galaxy_info': galaxy_info}
        display_result = gc._display_role_info(role_info)
        if display_result.find('\n\tgalaxy_info:') == -1:
            self.fail('Expected galaxy_info to be indented once')
    def test_run(self):