deps: bump gapic-generator-java-bom.version from 2.20.0 to 2.20.1

Bumps `gapic-generator-java-bom.version` from 2.20.0 to 2.20.1.

Updates `gapic-generator-java-bom` from 2.20.0 to 2.20.1
- [Release notes](https://github.com/googleapis/sdk-platform-java/releases)
- [Changelog](https://github.com/googleapis/sdk-platform-java/blob/main/CHANGELOG.md)
- [Commits](googleapis/sdk-platform-java@v2.20.0...v2.20.1)

Updates `gapic-generator-java` from 2.20.0 to 2.20.1
- [Release notes](https://github.com/googleapis/sdk-platform-java/releases)
- [Changelog](https://github.com/googleapis/sdk-platform-java/blob/main/CHANGELOG.md)
- [Commits](googleapis/sdk-platform-java@v2.20.0...v2.20.1)

---
updated-dependencies:
- dependency-name: com.google.api:gapic-generator-java-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: com.google.api:gapic-generator-java:testlib
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

spring-cloud-generator/pom.xml

@@ -15,7 +15,7 @@
     <description>Spring Code Generator for Google Cloud</description>
 
     <properties>
-        <gapic-generator-java-bom.version>2.20.0</gapic-generator-java-bom.version>
+        <gapic-generator-java-bom.version>2.20.1</gapic-generator-java-bom.version>
         <!-- [gapic-test]: protobuf.version for compiling protos used in unit testing
              this should be consistent with version in gapic-generator-java-bom -->
         <protobuf.version>3.21.12</protobuf.version>