adjust getPomVersion function signature

Jenkinsfile

@@ -77,7 +77,7 @@ pipeline {
           steps {
                 script {
                     FAILED_STAGE=env.STAGE_NAME
-                    JAR_TAG = getPomVersion('pom.xml').replace("SNAPSHOT", "${env.BRANCH_NAME}-SNAPSHOT")
+                    JAR_TAG = getPomVersion().replace("SNAPSHOT", "${env.BRANCH_NAME}-SNAPSHOT")
                 }
                 configFileProvider([configFile(fileId: 'maven-settings', variable: 'MAVEN_SETTINGS')]) {
                     sh "mvn -s $MAVEN_SETTINGS versions:set -DnewVersion=${JAR_TAG} -DprocessAllModules=true"
@@ -250,7 +250,7 @@ String getHelmRepoUrl(){
 }
 
 String generateHelmChartVersion() {
-    def chartVersion = getPomVersion('pom.xml')
+    def chartVersion = getPomVersion()
 
     if (isMainBranch()) {
         chartVersion += "-${env.GIT_COMMIT.take(7)}"
@@ -366,8 +366,8 @@ Void tagAndPushDockerImage(String imageName, String newTag){
     }
 }
 
-String getPomVersion(String pomFile){
-    def pom = readMavenPom file: pomFile
+String getPomVersion(){
+    def pom = readMavenPom file: 'pom.xml'
 
     return pom.version
 }