Bump com.spotify:dockerfile-maven-plugin from 1.4.12 to 1.4.13 (#1738)

Bumps [com.spotify: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](https://github.com/spotify/dockerfile-maven/compare/v1.4.12...v1.4.13)

---
updated-dependencies:
- dependency-name: com.spotify:dockerfile-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/pom.xml

@@ -67,7 +67,7 @@
 					<plugin>
 						<groupId>com.spotify</groupId>
 						<artifactId>dockerfile-maven-plugin</artifactId>
-						<version>1.4.12</version>
+						<version>1.4.13</version>
 						<configuration>
 							<repository>${docker.registry.organization}/${artifactId}</repository>
 							<tag>${project.version}</tag>

spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configuration-watcher/pom.xml

@@ -86,7 +86,7 @@
 					<plugin>
 						<groupId>com.spotify</groupId>
 						<artifactId>dockerfile-maven-plugin</artifactId>
-						<version>1.4.12</version>
+						<version>1.4.13</version>
 						<configuration>
 							<repository>${docker.registry.organization}/${artifactId}</repository>
 							<tag>${project.version}</tag>

spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-discoveryserver/pom.xml

@@ -59,7 +59,7 @@
 					<plugin>
 						<groupId>com.spotify</groupId>
 						<artifactId>dockerfile-maven-plugin</artifactId>
-						<version>1.4.12</version>
+						<version>1.4.13</version>
 						<configuration>
 							<repository>${docker.registry.organization}/${artifactId}</repository>
 							<tag>${project.version}</tag>