chore: upgrade build cache plugin to latest. (#12970)

As part of #337 I was trying to figure out how to why we have the 1.x and 2.x AWS SDK dependencies in our deps.toml today. Either one should be sufficient.

As part of this I noticed our build cache dependencies are out of date so I'm going to update this.

Upgrade this to the latest version - https://github.com/burrunan/gradle-s3-build-cache.

settings.gradle.kts

@@ -15,7 +15,7 @@ pluginManagement {
 // as much information as possible.
 plugins {
   id("com.gradle.enterprise") version "3.15.1"
-  id("com.github.burrunan.s3-build-cache") version "1.5"
+  id("com.github.burrunan.s3-build-cache") version "1.8.1"
 }
 
 gradleEnterprise {