feat(gradle): use java image for docker mode (#11316)

lib/manager/gradle-wrapper/artifacts-real.spec.ts

lib/manager/gradle-wrapper/artifacts.spec.ts

lib/manager/gradle-wrapper/artifacts.ts

lib/manager/gradle-wrapper/extract.ts

lib/manager/gradle-wrapper/util.spec.ts

lib/manager/gradle-wrapper/utils.ts

lib/manager/gradle/deep/__snapshots__/index.spec.ts.snap

lib/manager/gradle/deep/gradle-updates-report.spec.ts

lib/manager/gradle/deep/gradle-updates-report.ts

lib/manager/gradle/deep/index.spec.ts

lib/manager/gradle/deep/index.ts

lib/manager/gradle/deep/utils.ts

lib/manager/types.ts