Feature/sigmarule wildcard regex caseinsensitive#119 (#123)

* under constructing

* underconstructing

* fix rule file for SIGMA rule.

* wildcard case insensetive.

* refactor

* Update src/detections/rule.rs

add test triple backshash

Co-authored-by: itiB <is0312vx@ed.ritsumei.ac.jp>

* remove unnecessary if statement

Co-authored-by: itiB <is0312vx@ed.ritsumei.ac.jp>

rules/powershell/downgrade_attack.yml

@@ -8,7 +8,7 @@ detection:
     selection:
         Channel: Windows PowerShell
         EventID: 400
-        EventData: '[\s\S]*EngineVersion=2.0[\s\S]*'
+        EventData|re: '[\s\S]*EngineVersion=2\.0[\s\S]*'
 falsepositives:
     - unknown
 level: medium