Upgrade spotbugs-maven-plugin to 3.1.9

Change-Id: Idc447dfbcd165ef0362142bd17434d304c6c7f01
Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>

pom.xml

@@ -217,7 +217,7 @@
     <maven-javadoc-plugin-version>3.0.1</maven-javadoc-plugin-version>
     <tycho-extras-version>1.2.0</tycho-extras-version>
     <gson-version>2.8.2</gson-version>
-    <spotbugs-maven-plugin-version>3.1.8</spotbugs-maven-plugin-version>
+    <spotbugs-maven-plugin-version>3.1.9</spotbugs-maven-plugin-version>
     <maven-surefire-version>2.22.1</maven-surefire-version>
     <maven-compiler-plugin-version>3.8.0</maven-compiler-plugin-version>
     <maven-project-info-reports-plugin-version>3.0.0</maven-project-info-reports-plugin-version>