Bump dockerfile-maven-plugin from 1.4.12 to 1.4.13

Bumps [dockerfile-maven-plugin](https://github.com/spotify/dockerfile-maven) from 1.4.12 to 1.4.13.
- [Release notes](https://github.com/spotify/dockerfile-maven/releases)
- [Changelog](https://github.com/spotify/dockerfile-maven/blob/master/CHANGELOG.md)
- [Commits](spotify/dockerfile-maven@v1.4.12...v1.4.13)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

samples/mysql-schema/pom.xml

@@ -58,7 +58,7 @@
             <plugin>
                 <groupId>com.spotify</groupId>
                 <artifactId>dockerfile-maven-plugin</artifactId>
-                <version>1.4.12</version>
+                <version>1.4.13</version>
                 <configuration>
                     <repository>${docker-registry}/mysql-schema-operator</repository>
                     <tag>${project.version}</tag>

samples/webserver/pom.xml

@@ -53,7 +53,7 @@
             <plugin>
                 <groupId>com.spotify</groupId>
                 <artifactId>dockerfile-maven-plugin</artifactId>
-                <version>1.4.12</version>
+                <version>1.4.13</version>
                 <configuration>
                     <repository>webserver-operator</repository>
                     <tag>latest</tag>