Make pom.xml always reproducible

[snazy]

It turned out in practice, that there's no guarantee that the <parent> element in pom.xml files always appear at the same place.

This change ensures that the <parent> elements always appears at a deterministic location at the top of pom.xml files.

[snazy]

For posterity a pom.xml from 1.3.0-incubating-rc0's staging. Notice the XML elements at the end.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <!-- This module was also published with a richer model, Gradle metadata,  -->
  <!-- which should be used instead. Do not delete the following line which  -->
  <!-- is to indicate to Gradle or any Gradle module metadata file consumer  -->
  <!-- that they should prefer consuming it instead. -->
  <!-- do_not_remove: published-with-gradle-metadata -->
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.apache.polaris</groupId>
  <artifactId>polaris-persistence-nosql-benchmark</artifactId>
  <version>1.3.0-incubating</version>
  <packaging>pom</packaging>
  <licenses>
    <license>
      <name>Apache-2.0</name>
    </license>
  </licenses>
  <parent>
    <groupId>org.apache.polaris</groupId>
    <artifactId>polaris</artifactId>
    <version>1.3.0-incubating</version>
  </parent>
  <dependencies/>
</project>

And locally built:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <!-- This module was also published with a richer model, Gradle metadata,  -->
  <!-- which should be used instead. Do not delete the following line which  -->
  <!-- is to indicate to Gradle or any Gradle module metadata file consumer  -->
  <!-- that they should prefer consuming it instead. -->
  <!-- do_not_remove: published-with-gradle-metadata -->
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.apache.polaris</groupId>
  <artifactId>polaris-persistence-nosql-benchmark</artifactId>
  <version>1.3.0-incubating</version>
  <packaging>pom</packaging>
  <licenses>
    <license>
      <name>Apache-2.0</name>
    </license>
  </licenses>
  <dependencies/>
  <parent>
    <groupId>org.apache.polaris</groupId>
    <artifactId>polaris</artifactId>
    <version>1.3.0-incubating</version>
  </parent>
</project>

[dimas-b]

why append on line 61 and immediately remove here?