Test improvement

[peter279k]

Changed log

• Add php-7.4 version test on Travis CI build.
• The composer.lock file is not under Git version control and it should use composer install command during Travis CI build.

[coveralls]

Pull Request Test Coverage Report for Build 183

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 88.41%

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Totals
Change from base Build 181:	0.0%
Covered Lines:	656
Relevant Lines:	742

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💛 - Coveralls

[DivineOmega]

Thank you!