Bump software.amazon.awssdk:bom from 2.20.16 to 2.28.4

Bumps software.amazon.awssdk:bom from 2.20.16 to 2.28.4.

---
updated-dependencies:
- dependency-name: software.amazon.awssdk:bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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build.gradle

@@ -25,7 +25,7 @@ repositories {
 
 dependencies {
     implementation(platform('org.junit:junit-bom:5.8.1'))
-    implementation(platform("software.amazon.awssdk:bom:2.20.16"))
+    implementation(platform("software.amazon.awssdk:bom:2.28.4"))
 
     implementation('software.amazon.awssdk:codeartifact')
     implementation('software.amazon.awssdk:sts')