Fix for headers field_to_match #94

[MatanHeledPort]

Description

Lookup for field_to_match in headers wasn't scanning keys. This should fix the issue #94

Please explain the changes you made here and link to any relevant issues. Changed : lookup(match_pattern.value, "all", {} to: lookup(keys(match_pattern.value), "all", {}

[felipe88alves]

Only suggestion would be to remove the not statement from the example to keep the scope of the test simpler, not a blocker from merging anyways.

In any case , I can't approve but lgtm

[MatanHeledPort]

@Ohid25 Would appreciate a review here (:

[Ohid25]

Thank you for your contribution! This is now released as a part of 4.4.0.