chore(deps): update dependency org.apache.maven.plugins:maven-compiler-plugin to v3.15.0 (#930)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
|
[org.apache.maven.plugins:maven-compiler-plugin](https://maven.apache.org/plugins/)
([source](https://redirect.github.com/apache/maven-compiler-plugin)) |
`3.14.1` → `3.15.0` |
![age](https://developer.mend.io/api/mc/badges/age/maven/org.apache.maven.plugins:maven-compiler-plugin/3.15.0?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/maven/org.apache.maven.plugins:maven-compiler-plugin/3.14.1/3.15.0?slim=true)
|

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/line/line-bot-sdk-python).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi45NS4yIiwidXBkYXRlZEluVmVyIjoiNDIuOTUuMiIsInRhcmdldEJyYW5jaCI6Im1hc3RlciIsImxhYmVscyI6WyJkZXBlbmRlbmN5IHVwZ3JhZGUiXX0=-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

generator/pom.xml

@@ -97,7 +97,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.14.1</version>
+                <version>3.15.0</version>
                 <configuration>
                     <source>1.8</source>
                     <target>1.8</target>