deps: update dependency com.google.cloud:google-cloud-core to v2.8.20 (googleapis#1038)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.cloud:google-cloud-core](https://togithub.com/googleapis/java-core) | `2.8.19` -> `2.8.20` | [![age](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.20/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.20/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.20/compatibility-slim/2.8.19)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-core/2.8.20/confidence-slim/2.8.19)](https://docs.renovatebot.com/merge-confidence/) |

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java-video-intelligence/samples/install-without-bom/pom.xml

@@ -58,7 +58,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.19</version>
+      <version>2.8.20</version>
       <scope>test</scope>
       <classifier>tests</classifier>
     </dependency>

java-video-intelligence/samples/snapshot/pom.xml

@@ -52,7 +52,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.19</version>
+      <version>2.8.20</version>
       <scope>test</scope>
       <classifier>tests</classifier>
     </dependency>

java-video-intelligence/samples/snippets/pom.xml

@@ -63,7 +63,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-core</artifactId>
-      <version>2.8.19</version>
+      <version>2.8.20</version>
       <scope>test</scope>
       <classifier>tests</classifier>
     </dependency>