Bump icu4j from 70.1 to 71.1 (#161)

Bumps [icu4j](https://github.com/unicode-org/icu) from 70.1 to 71.1.
- [Release notes](https://github.com/unicode-org/icu/releases)
- [Commits](https://github.com/unicode-org/icu/commits)

---
updated-dependencies:
- dependency-name: com.ibm.icu:icu4j
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

planetiler-core/pom.xml

@@ -125,7 +125,7 @@
     <dependency>
       <groupId>com.ibm.icu</groupId>
       <artifactId>icu4j</artifactId>
-      <version>70.1</version>
+      <version>71.1</version>
     </dependency>
     <dependency>
       <groupId>com.google.guava</groupId>