I am facing an issue when using the datepicker package.
If I try to give an image to the cell decoration property, i get the following error.

"The following assertion was thrown during paint():
'package:flutter/src/painting/box_decoration.dart': Failed assertion: line 378 pos 12: 'onChanged != null || image == null': is not true."

This is how I am using it -
`
SfDateRangePicker(
minDate: DateTime(DateTime.now().year, DateTime.now().month),
maxDate: DateTime(DateTime.now().year, DateTime.now().month + 1, 0),
selectionTextStyle: TextStyle(color: AppColor.white),
monthViewSettings: DateRangePickerMonthViewSettings(
specialDates: leaveDays,

                        ),
                        monthCellStyle: DateRangePickerMonthCellStyle(
                          cellDecoration: BoxDecoration(
                            image: DecorationImage(
                              image: AssetImage('assets/icons/icon.png'),
                            ),
                          ),
                          specialDatesDecoration: BoxDecoration(
                            color: AppColor.saffron,
                            border: Border.all(color: AppColor.saffron, width: 1),
                            shape: BoxShape.circle,
                          ),
                        ),
                      ),

`

flutter doctor output -

[✓] Flutter (Channel stable, 1.22.1, on Mac OS X 10.15.6 19G2021, locale en-IN)
• Flutter version 1.22.1 at /Users/vaibhav/Documents/flutter
• Framework revision f30b7f4db9 (2 weeks ago), 2020-10-08 10:06:30 -0700
• Engine revision 75bef9f6c8
• Dart version 2.10.1

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
• Android SDK at /Users/vaibhav/Library/Android/sdk
• Platform android-30, build-tools 30.0.1
• ANDROID_HOME = /Users/vaibhav/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.0)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 12.0, Build version 12A7209
• CocoaPods version 1.9.3

[✓] Android Studio (version 4.0)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 46.0.2
• Dart plugin version 193.7361
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.50.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.15.1

[✓] Connected device (2 available)
• Android SDK built for x86 (mobile) • emulator-5554 • android-x86 • Android 7.1.1 (API 25) (emulator)
• iPhone 11 (mobile) • D1539A6B-139F-4F52-A9E9-6A051D602C62 • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-0 (simulator)

• No issues found!