chore(deps): bump software.amazon.awssdk:bom

Bumps software.amazon.awssdk:bom from 2.24.2 to 2.26.15.

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

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

Author: dependabot[bot]

TestVectors/runtimes/java/build.gradle.kts

@@ -92,7 +92,7 @@ dependencies {
     implementation("software.amazon.cryptography:aws-database-encryption-sdk-dynamodb:${ddbecVersion}")
     implementation("software.amazon.cryptography:TestAwsCryptographicMaterialProviders:${mplVersion}")
 
-    implementation(platform("software.amazon.awssdk:bom:2.24.2"))
+    implementation(platform("software.amazon.awssdk:bom:2.26.20"))
     implementation("software.amazon.awssdk:dynamodb")
     implementation("software.amazon.awssdk:dynamodb-enhanced")
     implementation("software.amazon.awssdk:core:2.24.7")