fix comparsion to undefined variable

.github/workflows/appimage.yml

@@ -61,7 +61,7 @@ jobs:
           POM_JFX_VERSION=${POM_JFX_VERSION#*@}
           POM_JFX_VERSION=${POM_JFX_VERSION%%.*}
 
-          if [ $POM_JFX_VERSION -ne $JMOD_VERSION_AMD64 ]; then
+          if [ $POM_JFX_VERSION -ne $JMOD_VERSION ]; then
             >&2 echo "Major JavaFX version in pom.xml (${POM_JFX_VERSION}) != amd64 jmod version (${JMOD_VERSION})"
             exit 1
           fi