rebase: Bump github.com/aws/aws-sdk-go-v2/service/sts

Bumps [github.com/aws/aws-sdk-go-v2/service/sts](https://github.com/aws/aws-sdk-go-v2) from 1.20.0 to 1.21.0.
- [Release notes](https://github.com/aws/aws-sdk-go-v2/releases)
- [Changelog](https://github.com/aws/aws-sdk-go-v2/blob/main/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-go-v2/compare/v1.20.0...service/s3/v1.21.0)

---
updated-dependencies:
- dependency-name: github.com/aws/aws-sdk-go-v2/service/sts
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/aws/smithy-go/endpoints/endpoint.go

@@ -0,0 +1,23 @@
+package transport
+
+import (
+	"net/http"
+	"net/url"
+
+	"github.com/aws/smithy-go"
+)
+
+// Endpoint is the endpoint object returned by Endpoint resolution V2
+type Endpoint struct {
+	// The complete URL minimally specfiying the scheme and host.
+	// May optionally specify the port and base path component.
+	URI url.URL
+
+	// An optional set of headers to be sent using transport layer headers.
+	Headers http.Header
+
+	// A grab-bag property map of endpoint attributes. The
+	// values present here are subject to change, or being add/removed at any
+	// time.
+	Properties smithy.Properties
+}