chore: use type-safe DSL instead of direct XML manipulation for pom.xml

[Fiouz]

Dedicated DSL usage should be safer in order to detect typos.

This has the side effect of changing the order of the XML elements, but
this is more canonical this way.

$ diff -u3 picocli-groovy/pom-default.xml picocli-groovy/build/publications/MyPublication/pom-default.xml
--- picocli-groovy/pom-default.xml 2021-02-21 11:18:23.755921800 +0800
+++ picocli-groovy/build/publications/MyPublication/pom-default.xml     2021-02-21 11:20:45.363477600 +0800
@@ -1,18 +1,10 @@
 <?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 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <modelVersion>4.0.0</modelVersion>
   <groupId>info.picocli</groupId>
   <artifactId>picocli-groovy</artifactId>
   <version>4.6.2-SNAPSHOT</version>
-  <dependencies>
-    <dependency>
-      <groupId>info.picocli</groupId>
-      <artifactId>picocli</artifactId>
-      <version>4.6.2-SNAPSHOT</version>
-      <scope>compile</scope>
-    </dependency>
-  </dependencies>
-  <packaging>jar</packaging>
   <name>picocli-groovy</name>
   <description>Picocli Groovy - easily use picocli in Groovy scripts.</description>
   <url>http://picocli.info</url>
@@ -32,8 +24,16 @@
     </developer>
   </developers>
   <scm>
-    <url>https://github.com/remkop/picocli/tree/master</url>
     <connection>scm:git:https://github.com/remkop/picocli.git</connection>
     <developerConnection>scm:git:ssh://github.com:remkop/picocli.git</developerConnection>
+    <url>https://github.com/remkop/picocli/tree/master</url>
   </scm>
+  <dependencies>
+    <dependency>
+      <groupId>info.picocli</groupId>
+      <artifactId>picocli</artifactId>
+      <version>4.6.2-SNAPSHOT</version>
+      <scope>compile</scope>
+    </dependency>
+  </dependencies>
 </project>

https://docs.gradle.org/4.8/release-notes.html#customizing-the-generated-pom
https://docs.gradle.org/current/userguide/publishing_maven.html#sec:modifying_the_generated_pom

[codecov]

Codecov Report

Merging #1330 (b561cfa) into master (c353a28) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #1330   +/-   ##
=========================================
  Coverage     93.79%   93.79%           
  Complexity      474      474           
=========================================
  Files             2        2           
  Lines          6961     6961           
  Branches       1869     1869           
=========================================
  Hits           6529     6529           
  Misses          146      146           
  Partials        286      286           

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[remkop]

Merged. Thank you for the contribution!
I will update the release notes soon.

[remkop]

Release notes are updated.
Thank you again for the contribution!