Bump version to 0.67.0

[imaNNeo]

• FEATURE (by @julien4215) Add direction property to the HorizontalLineLabel and VerticalLineLabel, #1574
• FEATURE (by @apekshamehta) Added new method called getTooltipColor for axis charts (bar,line,scatter) to change background color of tooltip dynamically.issue.
• BREAKING (by @apekshamehta) Removed tooltipBgColor property from Bar, Line and Scatter Charts (you can now use getTooltipColor which provides more customizability), checkout the full migration guide here.

  
  /// Migration guide:
  /// This is the old way:
  BarChartData(
  barTouchData: BarTouchData(
  touchTooltipData: BarTouchTooltipData(
    tooltipBgColor: Colors.blueGrey,
  )
  )
  )

/// This is the new way: BarChartData( barTouchData: BarTouchData( touchTooltipData: BarTouchTooltipData( getTooltipColor: (BarChartGroupData group) => Colors.blueGrey, ) ) )

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 87.52%. Comparing base (2d0ce64) to head (bdc5001).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1623 +/- ## ======================================= Coverage 87.52% 87.52% ======================================= Files 45 45 Lines 3078 3078 ======================================= Hits 2694 2694 Misses 384 384 ```

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