chore(deps): bump maven-compiler-plugin from 3.8.1 to 3.9.0 (#822)

Bumps [maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.8.1 to 3.9.0.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](apache/maven-compiler-plugin@maven-compiler-plugin-3.8.1...maven-compiler-plugin-3.9.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

Author: dependabot[bot]

pom.xml

@@ -57,7 +57,7 @@
         <micrometer-core.version>1.8.1</micrometer-core.version>
 
         <fmt-maven-plugin.version>2.11</fmt-maven-plugin.version>
-        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
+        <maven-compiler-plugin.version>3.9.0</maven-compiler-plugin.version>
         <maven-surefire-plugin.version>3.0.0-M5</maven-surefire-plugin.version>
         <maven-javadoc-plugin.version>3.3.1</maven-javadoc-plugin.version>
         <maven-resources-plugin.version>3.2.0</maven-resources-plugin.version>

sample-operators/mysql-schema/pom.xml

@@ -94,7 +94,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version>
+                <version>3.9.0</version>
             </plugin>
         </plugins>
     </build>

sample-operators/tomcat-operator/pom.xml

@@ -84,7 +84,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version>
+                <version>3.9.0</version>
             </plugin>
         </plugins>
     </build>

sample-operators/webpage/pom.xml

@@ -60,7 +60,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version>
+                <version>3.9.0</version>
             </plugin>
         </plugins>
     </build>