ci: javadoc on JDK 17

[suztomo]

Javadoc is not tested on JDK 17 and it caused a problem.

[INFO] <<< maven-javadoc-plugin:3.5.0:javadoc (default-cli) < generate-sources @ google-cloud-bigtable-stats <<<
[INFO] 
[INFO] 
[INFO] --- maven-javadoc-plugin:3.5.0:javadoc (default-cli) @ google-cloud-bigtable-stats ---
[INFO] No previous run data found, generating javadoc.
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] Google Cloud Bigtable Parent 2.24.0 ................ SUCCESS [  2.393 s]
[INFO] google-cloud-bigtable-stats 2.24.0 ................. FAILURE [  2.912 s]
[INFO] proto-google-cloud-bigtable-v2 2.24.0 .............. SKIPPED
[INFO] grpc-google-cloud-bigtable-v2 2.24.0 ............... SKIPPED
[INFO] proto-google-cloud-bigtable-admin-v2 2.24.0 ........ SKIPPED
[INFO] grpc-google-cloud-bigtable-admin-v2 2.24.0 ......... SKIPPED
[INFO] google-cloud-bigtable-emulator-core 0.161.0 ........ SKIPPED
[INFO] Google Cloud Java - Bigtable Emulator 0.161.0 ...... SKIPPED
[INFO] Google Cloud Bigtable 2.24.0 ....................... SKIPPED
[INFO] Google Cloud Bigtable BOM 2.24.0 ................... SKIPPED
[INFO] google-cloud-bigtable-deps-bom 2.24.0 .............. SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  7.245 s
[INFO] Finished at: 2023-06-27T18:22:24Z
[INFO] ------------------------------------------------------------------------
Error:  Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.5.0:javadoc (default-cli) on project google-cloud-bigtable-stats: An error has occurred in Javadoc report generation: 
Error:  Exit code: 1
Error: [ERROR] error: Malformed URL: [https://googleapis.dev/java/gax/${gax.version}/](https://googleapis.dev/java/gax/$%7Bgax.version%7D/) (java.net.URISyntaxException: Illegal character in path at index 33: [https://googleapis.dev/java/gax/${gax.version}/)](https://googleapis.dev/java/gax/$%7Bgax.version%7D/))
Error: [ERROR] error: Malformed URL: [https://googleapis.github.io/api-common-java/${google.api-common.version}/apidocs/](https://googleapis.github.io/api-common-java/$%7Bgoogle.api-common.version%7D/apidocs/) (java.net.URISyntaxException: Illegal character in path at index 46: [https://googleapis.github.io/api-common-java/${google.api-common.version}/apidocs/)](https://googleapis.github.io/api-common-java/$%7Bgoogle.api-common.version%7D/apidocs/))
Error: [ERROR] 2 errors

[generated-files-bot]

Warning: This pull request is touching the following templated files:

• .github/workflows/ci.yaml

[suztomo]

Removing the links indeed resolved the issue.

[suztomo]

This change will be overwritten by OwlBot postprocessor's template. So I created googleapis/synthtool#1819