ci: configure dependabot to monitor maven-war-plugin updates

Part of #1590

Author: php-coder

.github/dependabot.yml

@@ -15,6 +15,7 @@ updates:
       - dependency-name: "org.apache.maven.plugins:maven-compiler-plugin"
       - dependency-name: "org.apache.maven.plugins:maven-enforcer-plugin"
       - dependency-name: "org.apache.maven.plugins:maven-resources-plugin"
+      - dependency-name: "org.apache.maven.plugins:maven-war-plugin"
       - dependency-name: "org.jsoup:jsoup"
       - dependency-name: "org.liquibase:liquibase-core"
       - dependency-name: "org.projectlombok:lombok"