Update gradle to 8.5 for support building with java 21

[DinithHerath]

Hi @tananaev

• In the current configuration of the release build, java 21 is used to build the traccar distribution.
• In the gradle properties, we are still using the gradle-7.5.1-bin.zip as the gradle distribution.
• According to [1] and [2] gradle 7.5.1 only supports java 18 and this may result in failed builds for java 21.
• Therefore this PR updates the gradle to 8.5 which is the java 21 supported gradle distribution as per [1] and [3].

[1] https://docs.gradle.org/current/userguide/compatibility.html
[2] https://docs.gradle.org/7.5.1/release-notes.html?_gl=1*1jz7vqz*_ga*MTYwMjA0Mjg3LjE3MTI2MDU4NDc.*_ga_7W7NC6YNPT*MTcxMjYzNDY4OC4zLjEuMTcxMjYzNDc3Mi40Ny4wLjA.
[3] https://docs.gradle.org/8.5/release-notes.html?_gl=1*14d4mdc*_ga*MTYwMjA0Mjg3LjE3MTI2MDU4NDc.*_ga_7W7NC6YNPT*MTcxMjYzNDY4OC4zLjEuMTcxMjYzNDk1OC42MC4wLjA.

Thanks,
Dinith

[tananaev]

Looks like CI is failing.

[DinithHerath]

Looks like CI is failing.

This is due to the usage of the --warning-mode=fail flag in the gradle build command in the CI action. There are a couple of warnings with deprecation notices in the build process. If possible we can ignore this flag and build.

[tananaev]

No, ideally we fix the warnings.

[DinithHerath]

I just checked the warnings, seems like we need to rewrite the build gradle file as there are lot of deprecation warnings.