release-version only accepts valid numbers as version

It seems like release-version only accepts valid numbers as version (e.g. 1.8 is accepted, but 1.8.0 is not).

When trying to call
<r:release-version version="1.8.0" tag="tag_name" />

I get the following exception:

Caught exception evaluating: org.apache.commons.jexl.ExpressionImpl@8b1a4f. Reason: java.lang.NumberFormatException: multiple points
java.lang.NumberFormatException: multiple points
at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1067)
at java.lang.Double.valueOf(Double.java:202)
at java.lang.Double.<init>(Double.java:277)
at org.apache.commons.jexl.util.Coercion.coerceDouble(Coercion.java:160)
at org.apache.commons.jexl.parser.ASTSubtractNode.value(ASTSubtractNode.java:109)
at org.apache.commons.jexl.parser.ASTExpression.value(ASTExpression.java:85)
at org.apache.commons.jexl.ExpressionImpl.evaluate(ExpressionImpl.java:123)
at org.apache.commons.jelly.expression.jexl.JexlExpression.evaluate(JexlExpression.java:115)
at org.apache.commons.jelly.expression.jexl.JexlExpressionFactory$ExpressionSupportLocal.evaluate(JexlExpressionFactory.java:168)
at org.apache.commons.jelly.expression.ExpressionSupport.evaluateRecurse(ExpressionSupport.java:106)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:249)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:135)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:233)
at org.apache.commons.jelly.tags.core.IfTag.doTag(IfTag.java:88)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:279)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:135)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag.runBodyTag(MavenGoalTag.java:79)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag$MavenGoalAction.performAction(MavenGoalTag.java:110)
at com.werken.werkz.Goal.fire(Goal.java:639)
at com.werken.werkz.Goal.attain(Goal.java:575)
at com.werken.werkz.WerkzProject.attainGoal(WerkzProject.java:193)
at org.apache.maven.jelly.tags.werkz.MavenAttainGoalTag.doTag(MavenAttainGoalTag.java:127)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:279)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:135)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:233)
at org.apache.commons.jelly.tags.core.IfTag.doTag(IfTag.java:88)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:279)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:135)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag.runBodyTag(MavenGoalTag.java:79)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag$MavenGoalAction.performAction(MavenGoalTag.java:110)
at com.werken.werkz.Goal.fire(Goal.java:639)
at com.werken.werkz.Goal.attain(Goal.java:575)
at com.werken.werkz.WerkzProject.attainGoal(WerkzProject.java:193)
at org.apache.maven.jelly.tags.werkz.MavenAttainGoalTag.doTag(MavenAttainGoalTag.java:127)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:279)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:135)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag.runBodyTag(MavenGoalTag.java:79)
at org.apache.maven.jelly.tags.werkz.MavenGoalTag$MavenGoalAction.performAction(MavenGoalTag.java:110)
at com.werken.werkz.Goal.fire(Goal.java:639)
at com.werken.werkz.Goal.attain(Goal.java:575)
at com.werken.werkz.WerkzProject.attainGoal(WerkzProject.java:193)
at org.apache.maven.plugin.PluginManager.attainGoals(PluginManager.java:634)
at org.apache.maven.MavenSession.attainGoals(MavenSession.java:266)
at org.apache.maven.cli.App.doMain(App.java:486)
at org.apache.maven.cli.App.main(App.java:1215)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at com.werken.forehead.Forehead.run(Forehead.java:551)
at com.werken.forehead.Forehead.main(Forehead.java:581)