deps: update dependency com.google.cloud:google-cloud-core to v2.8.7 (#785)

[![Mend Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.cloud:google-cloud-core](https://togithub.com/googleapis/java-core) | `2.8.6` -> `2.8.7` | [![age](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.7/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.7/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.7/compatibility-slim/2.8.6)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.7/confidence-slim/2.8.6)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

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

### [`v2.8.7`](https://togithub.com/googleapis/java-core/blob/HEAD/CHANGELOG.md#&#8203;287-httpsgithubcomgoogleapisjava-corecomparev286v287-2022-08-03)

[Compare Source](https://togithub.com/googleapis/java-core/compare/v2.8.6...v2.8.7)

##### Dependencies

-   update dependency com.google.auth:google-auth-library-bom to v1.9.0 ([#&#8203;894](https://togithub.com/googleapis/java-core/issues/894)) ([82aaa16](https://togithub.com/googleapis/java-core/commit/82aaa16cd9813984a0c92d944eb1ad956759a8e5))
-   update dependency io.grpc:grpc-bom to v1.48.1 ([#&#8203;891](https://togithub.com/googleapis/java-core/issues/891)) ([0b0f9b8](https://togithub.com/googleapis/java-core/commit/0b0f9b89757b801e8334c764644d7b66032d36d1))

</details>

---

### Configuration

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

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, 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, click this checkbox.

---

This PR has been generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View repository job log [here](https://app.renovatebot.com/dashboard#github/googleapis/java-accessapproval).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzMi4xNDEuMCIsInVwZGF0ZWRJblZlciI6IjMyLjE0MS4wIn0=-->

Author: renovate-bot

samples/install-without-bom/pom.xml

@@ -48,7 +48,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.6</version>
+      <version>2.8.7</version>
       <classifier>tests</classifier>
     </dependency>
   </dependencies>

samples/snapshot/pom.xml

@@ -46,7 +46,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.6</version>
+      <version>2.8.7</version>
       <classifier>tests</classifier>
     </dependency>
   </dependencies>

samples/snippets/pom.xml

@@ -59,7 +59,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.6</version>
+      <version>2.8.7</version>
       <classifier>tests</classifier>
     </dependency>
   </dependencies>