Update petitparser dependencies

[sinhaaritro]

Why?

petitparser dependencies need to updated to the latest version

Because flutter_native_splash >=2.3.8 depends on xml ^6.5.0 and no versions of xml match >6.5.0 <7.0.0, flutter_native_splash >=2.3.8 requires xml 6.5.0.
And because xml 6.5.0 depends on petitparser ^6.0.0 and equations >=5.0.0 depends on petitparser ^5.4.0, flutter_native_splash >=2.3.8 is incompatible with equations >=5.0.0.
So, because fitneseo depends on both equations ^5.0.2 and flutter_native_splash ^2.4.0, version solving failed.

What?

I have updated the petitparser dependencies to ^6.0.2

Types of Changes

• General improvements (quality updates to improve the stability of the project)

Notes

With the latest version of Flutter SDK. The intl package in the example also needs to be updated to ^0.19.0

Checklist

• I have provided a description of the proposed changes.
• I added unit tests for all relevant code.
• In example/flutter_example, if needed, I have also added widget and golden tests.
• I added documentation for all relevant code.

[sinhaaritro]

Hi, it looks like I forgot to update the package version of the equation package from 5.0.2 to 5.0.3

[albertodev01]

Hello! I am updating everything now, you can close this PR and use the latest version

[albertodev01]

#55