fix: client initialization error with bootstrapped cache

[ErliSoares]

Description

When instantiating UnleashClient with cache set to cache.bootstrapped = True, the error Error loading features: 'BootstrapConnector' object has no attribute 'ready_callback' is returned.

The error occurs when calling the code block below. I was wondering if it's necessary, if initialize_client isn't the same thing.

unleash-python-sdk/UnleashClient/__init__.py

Lines 228 to 232 in 0bf3076

	if self.unleash_bootstrapped:
	BootstrapConnector(
	engine=self.engine,
	cache=self.cache,
	).start()

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• Unit tests
• Spec Tests
• Integration tests / Manual Tests

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[coveralls]

Pull Request Test Coverage Report for Build 19613145001

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.4%) to 93.411%

---

Files with Coverage Reduction	New Missed Lines	%
UnleashClient/connectors/base_connector.py	3	78.13%

Totals
Change from base Build 18272747945:	-0.4%
Covered Lines:	638
Relevant Lines:	683

---

💛 - Coveralls

[gastonfournier]

Checked with @sighphyre and this looks fine
Thanks for the contribution!