add pem postprocessor to the rules where pem detection applies

[grinish21]

example to add postprocessor -
`

• Code: 4005
  Pattern: "(?i).*\.pem$"
  Caption: Potential cryptographic private key
  Category: key
  Example: file.pem
  SolutionID: 11
  Severity: 4
  Confidence: 2
  Postprocess: ''
  `