tests: Replace "localhost" domain name with the equivalent IPv4 address #3473

Job	Run time
Build Cachi2 image and run integration tests on it	12m 29s
Build Cachi2 image and run integration tests on it	11m 21s
Build Cachi2 image and run integration tests on it	13m 39s
Hadolint	9s
Hadolint	9s
Hadolint	9s
Unit tests (3.9)	54s
Unit tests (3.9)	54s
Unit tests (3.9)	54s
Linters (bandit)	30s
Linters (bandit)	30s
Linters (bandit)	30s
Unit tests (3.10)	51s
Unit tests (3.10)	51s
Unit tests (3.10)	51s
Linters (black)	32s
Linters (black)	32s
Linters (black)	32s
Linters (isort)	31s
Linters (isort)	31s
Linters (isort)	31s
Unit tests (3.11)	47s
Unit tests (3.11)	47s
Unit tests (3.11)	47s
Linters (flake8)	32s
Linters (flake8)	32s
Linters (flake8)	32s
Unit tests (3.12)	57s
Unit tests (3.12)	57s
Unit tests (3.12)	57s
Linters (mypy)	53s
Linters (mypy)	53s
Linters (mypy)	53s
	57m 17s

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