refactor(example): remove unused modules and scripts

[lisabaut]

Description

While taking care of the dependabot PRs I saw that some modules are not in use in the example app:

• npm
• url
• buffer

Please take a closer look that I am not mistaken.
But in my opinion it looks like as these can be removed.

Additionally I found the script upgradeExample.sh which was created 2 years ago and contains hard coded module versions which - if this script is used by people - should acually be maintained and upgraded too with each dependabot PR, correct? But as I could not find any usage of this script nor a hint in the docs I removed it as well.
Also because there are other ways on how to upgrade react-native (upgrade helper, CLI => see the docs)

After the merge I would close this PR here then: https://github.com/react-native-mapbox-gl/maps/pull/1610

Checklist

• I have tested this on a device/simulator for each compatible OS
• I formatted JS and TS files with yarn lint
• I updated the documentation yarn generate
• I mentioned this change in CHANGELOG.md
• I updated the typings files (index.d.ts)
• I added/ updated a sample (/example)

Screenshot OR Video

[ferdicus]

Thanks for opening this @lisabaut,
seems like these are only required for the upgradeExample script - good find 👍🏿

@RobertSasak, as you introduced this script - do you think this is still relevant?

Cheers 🍻

[RobertSasak]

Good job. The upgradeExample.sh is not needet any more and can be deleted.