build(deps): update dependency com.google.cloud:google-cloud-shared-config to v1.5.3 (#730)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.cloud:google-cloud-shared-config](https://togithub.com/googleapis/java-shared-config) | `1.5.1` -> `1.5.3` | [![age](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-shared-config/1.5.3/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-shared-config/1.5.3/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-shared-config/1.5.3/compatibility-slim/1.5.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.cloud:google-cloud-shared-config/1.5.3/confidence-slim/1.5.1)](https://docs.renovatebot.com/merge-confidence/) |

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Author: renovate-bot

java-tasks/google-cloud-tasks-bom/pom.xml

@@ -8,7 +8,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-shared-config</artifactId>
-    <version>1.5.1</version>
+    <version>1.5.3</version>
   </parent>
 
   <name>Google Cloud tasks BOM</name>

java-tasks/pom.xml

@@ -14,7 +14,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-shared-config</artifactId>
-    <version>1.5.1</version>
+    <version>1.5.3</version>
   </parent>
 
   <developers>