Update opentelemetry_sdk requirement from 0.28 to 0.29

Updates the requirements on [opentelemetry_sdk](https://github.com/open-telemetry/opentelemetry-rust) to permit the latest version.
- [Release notes](https://github.com/open-telemetry/opentelemetry-rust/releases)
- [Commits](open-telemetry/opentelemetry-rust@opentelemetry_sdk-0.28.0...opentelemetry_sdk-0.29.0)

---
updated-dependencies:
- dependency-name: opentelemetry_sdk
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -42,7 +42,7 @@ opentelemetry-prometheus = { version = "0.28", optional = true }
 opentelemetry-semantic-conventions = { version = "0.28", features = [
   "semconv_experimental",
 ] }
-opentelemetry_sdk = { version = "0.28", optional = true, features = [
+opentelemetry_sdk = { version = "0.29", optional = true, features = [
   "metrics",
   "rt-tokio-current-thread",
 ] }
@@ -57,7 +57,7 @@ actix-web-opentelemetry = { path = ".", features = [
   "sync-middleware",
   "awc",
 ] }
-opentelemetry_sdk = { version = "0.28", features = [
+opentelemetry_sdk = { version = "0.29", features = [
   "spec_unstable_metrics_views",
   "metrics",
   "rt-tokio-current-thread",