Bumping S3 Secrets plugin to v2.5.0

Bumping version to v2.5.0 in order to enable the functionality of full secret redaction

Fixes #1471

Author: JoeColeman95

.gitmodules

@@ -1,7 +1,7 @@
 [submodule "plugins/secrets"]
 	path = plugins/secrets
 	url = https://github.com/buildkite/elastic-ci-stack-s3-secrets-hooks.git
-	branch = v2.1.6
+	branch = v2.5.0
 
 [submodule "plugins/ecr"]
 	path = plugins/ecr