[PATCH 4 of 4] Add plugin versions where missing

[Wald Commits]

# HG changeset patch
# User Tom Gottfried <tom at intevation.de>
# Date 1590775621 -7200
#      Fri May 29 20:07:01 2020 +0200
# Branch 3.2.x
# Node ID faccc67cac1d7cc3f77226d85a7b490b0b522fa4
# Parent  59ad66feb8f8902a549d4236efda3ed0056d1216
Add plugin versions where missing

For maven-jar-plugin, use the same version as already added
in the default branch to avoid later merge conflicts.

diff -r 59ad66feb8f8 -r faccc67cac1d backend/pom-oracle.xml
--- a/backend/pom-oracle.xml	Fri May 29 19:25:55 2020 +0200
+++ b/backend/pom-oracle.xml	Fri May 29 20:07:01 2020 +0200
@@ -46,6 +46,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
+        <version>2.4</version>
         <configuration>
           <archive>
             <manifest>
diff -r 59ad66feb8f8 -r faccc67cac1d backend/pom.xml
--- a/backend/pom.xml	Fri May 29 19:25:55 2020 +0200
+++ b/backend/pom.xml	Fri May 29 20:07:01 2020 +0200
@@ -46,6 +46,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
+        <version>2.4</version>
         <configuration>
           <archive>
             <manifest>
diff -r 59ad66feb8f8 -r faccc67cac1d gwt-client/pom.xml
--- a/gwt-client/pom.xml	Fri May 29 19:25:55 2020 +0200
+++ b/gwt-client/pom.xml	Fri May 29 20:07:01 2020 +0200
@@ -172,6 +172,7 @@
       <!-- Add source folders to test classpath in order to run gwt-tests as normal junit-tests -->
       <plugin>
         <artifactId>maven-surefire-plugin</artifactId>
+        <version>2.22.1</version>
         <configuration>
           <additionalClasspathElements>
             <additionalClasspathElement>${project.build.sourceDirectory}</additionalClasspathElement>
@@ -193,6 +194,7 @@
       <!-- Copy static web files before executing gwt:run -->
       <plugin>
         <artifactId>maven-resources-plugin</artifactId>
+        <version>3.1.0</version>
         <executions>
           <execution>
             <phase>compile</phase>
@@ -214,6 +216,7 @@
       <!-- Delete gwt generated stuff -->
       <plugin>
         <artifactId>maven-clean-plugin</artifactId>
+        <version>3.1.0</version>
         <configuration>
           <filesets>
             <fileset><directory>src/main/webapp/flys</directory></fileset>