Update frontend-maven-plugin to 1.12.0 (#119)

diff --git a/pom.xml b/pom.xml
index 2f9504c..3095b1c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -43,7 +43,7 @@
         <spring-boot.version>1.5.21.RELEASE</spring-boot.version>
         <apache-rat-plugin.version>0.12</apache-rat-plugin.version>
         <maven-compiler-plugin.version>3.3</maven-compiler-plugin.version>
-        <frontend-maven-plugin.version>1.6</frontend-maven-plugin.version>
+        <frontend-maven-plugin.version>1.12.0</frontend-maven-plugin.version>
         <os-maven-plugin.version>1.5.0.Final</os-maven-plugin.version>
         <takari-maven-plugin.version>0.6.1</takari-maven-plugin.version>
         <openjpa.version>3.1.2</openjpa.version>