NPE in loadLicenseInfo when the licenses.xml file contains licenses without <file>

[ppalaga]

Reported by @TorstenKruse . I think @k-wall mentioned the same thing.

[14:34:18] [ERROR] Failed to execute goal org.codehaus.mojo:license-maven-plugin:1.17-SNAPSHOT:aggregate-download-licenses (default-cli) on project pad: Unable to parse license summary output file: e:\Projects_git\pad\target\generated-resources\licenses.xml: NullPointerException -[Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:license-maven-plugin:1.17-SNAPSHOT:aggregate-download-licenses (default-cli) on project pad: Unable to parse license summary output file: e:\Projects_git\pad\target\generated-resources\licenses.xml
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:564)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Unable to parse license summary output file: e:\Projects_git\pad\target\generated-resources\licenses.xml
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.loadLicenseInfo(AbstractDownloadLicensesMojo.java:597)
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.execute(AbstractDownloadLicensesMojo.java:334)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
	... 20 more
Caused by: java.lang.NullPointerException
	at java.base/java.io.File.<init>(File.java:359)
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.loadLicenseInfo(AbstractDownloadLicensesMojo.java:590)
	... 23 more