address zizmor issues, remove 3p action for creating release for java

[bobcallaway]

This fixes issues reported by zizmor 🌈, as well as removing a dependency on a third-party action when the gh CLI should work just fine.

This also moves the gradle wrapper validation check to a non-deprecated action.

@loosebazooka @woodruffw fyi

[loosebazooka]

Java stuff looks good to me, ideally next step we add access to a pgp key to do the release to sonatype directly. We already have a java releasers group with permissions to write to the dev.sigstore on maven central

[bobcallaway]

Java stuff looks good to me, ideally next step we add access to a pgp key to do the release to sonatype directly. We already have a java releasers group with permissions to write to the dev.sigstore on maven central

yup, i'll do that in a separate PR

[woodruffw]

LGTM on the zizmor side!