Update repo with latest library versions

[nowshad-hasan]

I've made some changes regarding these issues:

1. Create a notification channel for devices>=Oreo
2. Remove version related deprecated code from manifest and gradle files
3. Migrate to androidx
4. Update gradle distribution to 5.4.1
5. Update gradle build to 3.5.3
6. Make TargetSdkVersion to 29(android 10)
7. Make source compatibility to JAVA 1.8
8. Update version-name and version-code

[AntonioRedondo]

Hi @nowshad-hasan! I missed the GitHub notification for this pull request among many other notifications. 😓 Let me have a look to the changes. 👀

[AntonioRedondo]

Fantastic job! Thank you for taking the time to update the build configuration!
The app runs again in the emulator with the latest Android SDK! 👍👍👍👍👍👍👍

[AntonioRedondo]

@nowshad-hasan if you cannot merge the pull request tell me and I'll do it.

[nowshad-hasan]

Hi @AntonioRedondo, you can merge this pull request because I don't think I've got the permission to do it. And really thanks for your PR review.

[nowshad-hasan]

Hi @AntonioRedondo , I accidentally made the commits with my job email not the regular email my GitHub is connected to. So, my profile is not shown up on the contributors list. Is there any workaround to solve this? Though this PR is showing on my profile. So, if it's a huge mess up for you, that will be completely unnecessary.

[AntonioRedondo]

@nowshad-hasan ouch, that really sucks! I removed last changes. Open another pull request with the right email account and I'll merged it.

[nowshad-hasan]

Hi @AntonioRedondo , I've made another PR with my regular email.

[AntonioRedondo]

[nowshad-hasan]

Hi @AntonioRedondo , really thanks for your effort to make the Revert and accept my PR again. But to get the idea, how do you revert master branch without changing the commit SHA-1 as like as before? Actually, I'm kind of noob about git!

[AntonioRedondo]

I don't think you can actually do that if you have pushed your changes. You can remove any number of commits in a branch, even if commits where pushed. But then any new commit will have a different hash.

What I did to revert your changes was:

git reset --hard HEAD~1 // It will erase any commit after HEAD~1, in this case, your PR changes
git push -f // We need to push to master the above changes. It's a destructive operation as we're forcing (-f) our branch history over the existing one in the repo.

Then merge your pull request. But the new commit in master will have a different hash than the one removed.

[nowshad-hasan]

Oh! That's great. Thanks for the idea 😃 .