Build fails on Flutter v1.17+

[royarg02]

Running flutter run on v1.0.3 results in compilation error:

Compiler message:
/home/anurag/.pub-cache/hosted/pub.dartlang.org/syncfusion_flutter_charts-1.0.0-beta.4/lib/src/common/user_interaction/t
ooltip.dart:312:32: Error: Constant evaluation error:
    _painter.getLocation(const Offset(null, null));                     
                               ^                                        
org-dartlang-sdk:///flutter/lib/ui/geometry.dart:16:9: Context: This assertion failed.
  const OffsetBase(double dx, double dy)                                
        ^                                                               
                                                                        
Compiler message:                                                       
/home/anurag/.pub-cache/hosted/pub.dartlang.org/syncfusion_flutter_charts-1.0.0-beta.4/lib/src/common/user_interaction/tooltip.dart:312:32: Error: Constant evaluation error:
    _painter.getLocation(const Offset(null, null));                     
                               ^                                        
org-dartlang-sdk:///flutter/lib/ui/geometry.dart:16:9: Context: This assertion failed.
  const OffsetBase(double dx, double dy)                                
        ^                                                               
Target kernel_snapshot failed: Exception: Errors during snapshot creation: null
build failed.                                                           
                                                                        
FAILURE: Build failed with an exception.                                
                                                                        
* Where:                                                                
Script '/home/anurag/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 882
                                                                        
* What went wrong:                                                      
Execution failed for task ':app:compileFlutterBuildDebug'.              
> Process 'command '/home/anurag/flutter/bin/flutter'' finished with non-zero exit value 1
                                                                        
* Try:                                                                  
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
                                                                        
* Get more help at https://help.gradle.org                              
                                                                        
BUILD FAILED in 19s

The issue seems to be related to syncfusion_flutter_charts package:
https://github.com/RoyARG02/soil_moisture_app/blob/fef3e73b2a24079817ca77b7aecf883b4a0bed5c/pubspec.yaml#L13
Considering that the app is using a beta version of the package. We need to either:

• use a recent version of the above package, or
• look for some other package for charting.

A viable alternative could be the charts_flutter package.

[royarg02]

Issue has been fixed on the stable release(v1.1.0) as of commit 50c63f1.