feat(secrets): Add multiline detection to entropy keyword combinator

[marynaKK]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

• changed the logic of parsing yml files (part of changes of IAC secret detection): secret and keyword appearing in the context of a line should be also parsed as a pair, and the secret should be detected.

for IAC files only keyword combination is supported. this addition supports also multiline combination.

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
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[nimrodkor]

@marynaKK Very nice job!

[nimrodkor]

We will move all yaml related methods to OOP to allow easier implementations for other extensions in another PR. GJ!

[gruebel]

nice, work, just have some minor comments

[gruebel]

🐶