Use net.alchim31.maven:scala-maven-plugin instead of org.scala-tools:maven-scala-plugin

org.scala-tools:maven-scala-plugin is not maintained since a long time.

[net.alchim31.maven:scala-maven-plugin](https://github.com/davidB/scala-maven-plugin) is the replacement.

Also Scala version could be upgraded from 2.12.8 to 2.12.13

Few other Maven plugins also could be upgraded.

**Reporter**: [Martin Tzvetanov Grigorov](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=mgrigorov) / @martin-g
#### PRs and other links:
- [Pull Request](https://github.com/apache/parquet-mr/pull/866)

_{**Note**: *This issue was originally created as [PARQUET-1976](https://issues.apache.org/jira/browse/PARQUET-1976). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start by inspecting the Maven build configuration for org.scala-tools:maven-scala-plugin and the Scala 2.12.8 version. Review the linked Pull Request 866 and migration documentation, then verify that the replacement plugin and stated version updates are reflected and the Maven build still passes.

Written by the indexing model from the issue text.