HADOOP-18197. Upgrade Protobuf-Java to 3.21.12 (#26)


This patch bumps up the protobuf version so that Hadoop
is not a vulnerable to CVE-2021-22569.

This does rename the module hadoop-shaded-protobuf_3_7
because that significantly complicates imports/upgrading.

This also fixes up the parent POM references in the child modules
as IntelliJ requires a full path.

Contributed by PJ Fanning
5 files changed