Use assignment to set repository url in Groovy Gradle builds

[hpoettker]

Summary

Gradle builds using Groovy, which use custom Maven repositories like the Spring milestone or snapshot repos, currently log deprecation warnings as they use the syntax

maven { url 'https://repo.spring.io/snapshot' }

instead of the preferred

maven { url = 'https://repo.spring.io/snapshot' }

Gradle's guidance on this is available here: https://docs.gradle.org/8.14/userguide/upgrading_version_8.html#groovy_space_assignment_syntax

The PR resolves this issue.

How to reproduce

In the Spring Initializr, build a Gradle project with Groovy and choose a Spring Boot snapshot release.

When one then executes for example

./gradlew clean --warning-mode all

the build will log

Settings file 'settings.gradle': line 3
Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated. This is scheduled to be removed in Gradle 10.0. Use assignment ('url = <value>') instead. Consult the upgrading guide for further information: https://docs.gradle.org/8.14/userguide/upgrading_version_8.html#groovy_space_assignment_syntax
        at settings_8j6gtdsyzf202bs1oyal9e9vj$_run_closure1$_closure2$_closure3.doCall$original(settings.gradle:3)
        (Run with --stacktrace to get the full stack trace of this deprecation warning.)
        at settings_8j6gtdsyzf202bs1oyal9e9vj$_run_closure1$_closure2.doCall$original(settings.gradle:3)
        (Run with --stacktrace to get the full stack trace of this deprecation warning.)

> Configure project :
Build file 'build.gradle': line 18
Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated. This is scheduled to be removed in Gradle 10.0. Use assignment ('url = <value>') instead. Consult the upgrading guide for further information: https://docs.gradle.org/8.14/userguide/upgrading_version_8.html#groovy_space_assignment_syntax
        at build_4owna3ovmuwuctycxsbmt7eu6$_run_closure2$_closure6.doCall$original(build.gradle:18)
        (Run with --stacktrace to get the full stack trace of this deprecation warning.)
        at build_4owna3ovmuwuctycxsbmt7eu6$_run_closure2.doCall$original(build.gradle:18)
        (Run with --stacktrace to get the full stack trace of this deprecation warning.)

[mhalbritter]

Hello,

thanks for the PR. This fixes the warning in the settings.gradle file, however in the build.gradle file I still got this:

repositories {
	mavenCentral()
	maven { url 'https://repo.spring.io/milestone' }
	maven { url 'https://repo.spring.io/snapshot' }
}

Could you fix that in GroovyDslGradleBuildWriter, too?

[hpoettker]

done

[mhalbritter]

Thanks @hpoettker !