Bug Fix: Fix Inline Dictionary For YAML Files

[jpdakran]

Problem

• When running detect-secrets on YAML files - there is a miscalculation that occurs when calculating the line number of an inline dictionary (FlowMapping).
• This is an issue with the PyYAML library.
• This issue occurs when there is an empty line after the inline dictionary.
• An example of where the miscalculation occurs:

dictionary: 
     - {keyA: valueA, keyB: valueB, keyC: valueC}
     

Solution

• This solution was inspired by this PR but was expanded on to fix a few other use-cases
• The parser keeps track of the the start of the FlowMapping character under self.marks
• We need to use this values line number when the inline dictionary has a key on the same line as the start of the FlowMapping.
• The PR above handles the case only when there is a SINGLE key value pair followed by an empty line. Ex. {key: value}
• To handle the cases where there are multiple key value pairs on a single line - we must check that the next upcoming tokens are of type FlowEntryToken, KeyToken (Comma, new Key). This will tell us if this dictionary has more values on the same line. Ex. {keyA: valueA, keyB: valueB, keyC: valueC}

Verification

• A suite of unit tests were created to validate the approach.

[KevinHock]

Great stuff @jpdakran!