deps: update dependency io.grpc:grpc-protobuf to v1.42.1 (#235)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [io.grpc:grpc-protobuf](https://github.com/grpc/grpc-java) | `1.42.0` -> `1.42.1` | [![age](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-protobuf/1.42.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-protobuf/1.42.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-protobuf/1.42.1/compatibility-slim/1.42.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/io.grpc:grpc-protobuf/1.42.1/confidence-slim/1.42.0)](https://docs.renovatebot.com/merge-confidence/) |

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### Release Notes

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

### [`v1.42.1`](https://github.com/grpc/grpc-java/releases/v1.42.1)

Bug fixes:

-   xds: fix a bug that invalid resources from the control plane was internally classified as missing configuration, but instead it should be classified as a transient error. This will change load balancing states on failure handling behavior: for example, missing LDS at xDS server would make it enter “not serving” mode but a transient error does not affect serving status. [#&#8203;8690](https://github.com/grpc/grpc-java/issues/8690)
-   xds: fix a bug where XdsServer didn’t block start() when configuration is missing, and instead errored. [#&#8203;8690](https://github.com/grpc/grpc-java/issues/8690)
-   xds: stop generating UUIDs for filter chains that lack them. The UUID was preventing the `XdsServer` from noticing when a control plane sent a needless duplicate update, causing `XdsServer` to drain all its existing connections to use the “new” configuration [#&#8203;8688](https://github.com/grpc/grpc-java/issues/8688)

New feature:

-   netty: Add ability to set system property `-Dio.grpc.netty.disableConnectionHeaderCheck=false` to disable HTTP Connection header check. This is a temporary workaround to allow fixing out-of-spec HTTP/2 clients [#&#8203;8683](https://github.com/grpc/grpc-java/issues/8683)
-   compiler: Protoc plugin for macOS x86 is duplicated to be used on the aarch architecture, to ease use on arm64 macs. The plugin is not actually ARM64, just named as such. Future work will need to compile it appropriately [#&#8203;8680](https://github.com/grpc/grpc-java/issues/8680)

</details>

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grpc-google-iam-v1/build.gradle

@@ -19,7 +19,7 @@ repositories {
 
 dependencies {
   compile 'io.grpc:grpc-stub:1.42.1'
-  compile 'io.grpc:grpc-protobuf:1.42.0'
+  compile 'io.grpc:grpc-protobuf:1.42.1'
   compile project(':proto-google-iam-v1')
 }