deps: update gax.version to v2.5.0 (googleapis#479)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.api:gax-grpc](https://github.com/googleapis/gax-java) | `2.4.1` -> `2.5.0` | [![age](https://badges.renovateapi.com/packages/maven/com.google.api:gax-grpc/2.5.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.api:gax-grpc/2.5.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.api:gax-grpc/2.5.0/compatibility-slim/2.4.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.api:gax-grpc/2.5.0/confidence-slim/2.4.1)](https://docs.renovatebot.com/merge-confidence/) |
| [com.google.api:gax-bom](https://github.com/googleapis/gax-java) | `2.4.1` -> `2.5.0` | [![age](https://badges.renovateapi.com/packages/maven/com.google.api:gax-bom/2.5.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.api:gax-bom/2.5.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.api:gax-bom/2.5.0/compatibility-slim/2.4.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.api:gax-bom/2.5.0/confidence-slim/2.4.1)](https://docs.renovatebot.com/merge-confidence/) |

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### Release Notes

<details>
<summary>googleapis/gax-java</summary>

### [`v2.5.0`](https://github.com/googleapis/gax-java/blob/master/CHANGELOG.md#&#8203;250-httpswwwgithubcomgoogleapisgax-javacomparev241v250-2021-09-21)

[Compare Source](https://github.com/googleapis/gax-java/compare/v2.4.1...v2.5.0)

##### Features

-   Add REST AIP-151 LRO support ([#&#8203;1484](https://www.github.com/googleapis/gax-java/issues/1484)) ([95ca348](https://www.github.com/googleapis/gax-java/commit/95ca3482d272b5c5c5ac2c85ba007f0ba9f7b5cf))

##### [2.4.1](https://www.github.com/googleapis/gax-java/compare/v2.4.0...v2.4.1) (2021-09-08)

##### Bug Fixes

-   REGAPIC fix socket timeout for wait calls ([#&#8203;1476](https://www.github.com/googleapis/gax-java/issues/1476)) ([86c68b3](https://www.github.com/googleapis/gax-java/commit/86c68b3ffd241f6932516d0e7b5d9ae5714b89e0))

</details>

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first-party-dependencies/pom.xml

@@ -56,7 +56,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <site.installationModule>${project.artifactId}</site.installationModule>
     <grpc.version>1.40.1</grpc.version>
-    <gax.version>2.4.1</gax.version>
+    <gax.version>2.5.0</gax.version>
     <grpc-gcp.version>1.1.0</grpc-gcp.version>
     <guava.version>30.1.1-jre</guava.version>
     <protobuf.version>3.17.3</protobuf.version>