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/properties.go

@@ -0,0 +1,52 @@
+package smithy
+
+// PropertiesReader provides an interface for reading metadata from the
+// underlying metadata container.
+type PropertiesReader interface {
+	Get(key interface{}) interface{}
+}
+
+// Properties provides storing and reading metadata values. Keys may be any
+// comparable value type. Get and set will panic if key is not a comparable
+// value type.
+//
+// Properties uses lazy initialization, and Set method must be called as an
+// addressable value, or pointer. Not doing so may cause key/value pair to not
+// be set.
+type Properties struct {
+	values map[interface{}]interface{}
+}
+
+// Get attempts to retrieve the value the key points to. Returns nil if the
+// key was not found.
+//
+// Panics if key type is not comparable.
+func (m *Properties) Get(key interface{}) interface{} {
+	return m.values[key]
+}
+
+// Set stores the value pointed to by the key. If a value already exists at
+// that key it will be replaced with the new value.
+//
+// Set method must be called as an addressable value, or pointer. If Set is not
+// called as an addressable value or pointer, the key value pair being set may
+// be lost.
+//
+// Panics if the key type is not comparable.
+func (m *Properties) Set(key, value interface{}) {
+	if m.values == nil {
+		m.values = map[interface{}]interface{}{}
+	}
+	m.values[key] = value
+}
+
+// Has returns whether the key exists in the metadata.
+//
+// Panics if the key type is not comparable.
+func (m *Properties) Has(key interface{}) bool {
+	if m.values == nil {
+		return false
+	}
+	_, ok := m.values[key]
+	return ok
+}