deps: update dependency io.grpc:grpc-stub to v1.50.2 (#477)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [io.grpc:grpc-stub](https://togithub.com/grpc/grpc-java) | `1.49.2` -> `1.50.2` | [![age](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-stub/1.50.2/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-stub/1.50.2/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-stub/1.50.2/compatibility-slim/1.49.2)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-stub/1.50.2/confidence-slim/1.49.2)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>grpc/grpc-java</summary>

### [`v1.50.2`](https://togithub.com/grpc/grpc-java/releases/tag/v1.50.2)

[Compare Source](https://togithub.com/grpc/grpc-java/compare/v1.50.1...v1.50.2)

##### Bug fixes

gcp-observability: Supports period(.) in the service name part of regular expression for a fully-qualified method to accept "package.service"

### [`v1.50.1`](https://togithub.com/grpc/grpc-java/releases/tag/v1.50.1)

[Compare Source](https://togithub.com/grpc/grpc-java/compare/v1.50.0...v1.50.1)

gcp-observability: support new configuration defined in grpc-gcp-observability public preview user guide

### [`v1.50.0`](https://togithub.com/grpc/grpc-java/releases/tag/v1.50.0)

[Compare Source](https://togithub.com/grpc/grpc-java/compare/v1.49.2...v1.50.0)

#### New Features

-   okhttp: Added connection management features to okhttp server, including maxConnectionIdle(),  permitKeepAliveTime(), and permitKeepAliveWithoutCalls() ([#&#8203;9494](https://togithub.com/grpc/grpc-java/issues/9494), [#&#8203;9544](https://togithub.com/grpc/grpc-java/issues/9544))
-   binder: Add `SecurityPolicies` for checking device owner/profile owner ([#&#8203;9428](https://togithub.com/grpc/grpc-java/issues/9428))

#### API Changes

-   api: Add LoadBalancer.acceptResolvedAddresses() ([#&#8203;9498](https://togithub.com/grpc/grpc-java/issues/9498)). The method is like `handleResolvedAddresses()` but returns a `boolean` of whether the addresses and configuration were accepted. Not accepting the update triggers the NameResolver to retry after a delay. We are not yet encouraging migration to this method, as there is still a second future API change
-   core: add CallOptions to CallCredentials.RequestInfo ([#&#8203;9538](https://togithub.com/grpc/grpc-java/issues/9538))

#### Bug Fixes

-   auth: Fix AppEngine failing while retrieving access token when instantiating a blocking stub using AppEngineCredentials ([#&#8203;9504](https://togithub.com/grpc/grpc-java/issues/9504))
-   core: Ensure that context cancellationCause is set ([#&#8203;9501](https://togithub.com/grpc/grpc-java/issues/9501))
-   core: Update outlier detection max ejection logic to allow exceeding the limit by one, to match Envoy. ([#&#8203;9489](https://togithub.com/grpc/grpc-java/issues/9489), [#&#8203;9492](https://togithub.com/grpc/grpc-java/issues/9492))
-   core: outlier detection to honor min host request volume ([#&#8203;9490](https://togithub.com/grpc/grpc-java/issues/9490))
-   okhttp: Add timeout for HTTP CONNECT proxy handshake ([#&#8203;9586](https://togithub.com/grpc/grpc-java/issues/9586))
-   xds: ringhash policy in TRANSIENT_FAILURE should not attempt connecting when already in connecting ([#&#8203;9535](https://togithub.com/grpc/grpc-java/issues/9535)). With workloads where most requests have the same hash, ring hash should behave more like pick-first of slowly trying backends

#### Dependencies

-   netty: upgrade netty from 4.1.77.Final to 4.1.79.Final and tcnative from 2.0.53 to 2.0.54 ([#&#8203;9451](https://togithub.com/grpc/grpc-java/issues/9451))

#### Acknowledgements

[@&#8203;cpovirk](https://togithub.com/cpovirk)
[@&#8203;prateek-0](https://togithub.com/prateek-0)
[@&#8203;sai-sunder-s](https://togithub.com/sai-sunder-s)

</details>

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grpc-google-iam-v1/build.gradle

@@ -18,7 +18,7 @@ repositories {
 }
 
 dependencies {
-  compile 'io.grpc:grpc-stub:1.49.2'
+  compile 'io.grpc:grpc-stub:1.50.2'
   compile 'io.grpc:grpc-protobuf:1.50.0'
   compile project(':proto-google-iam-v1')
 }