build(deps): Bump AWSSDK.EC2 from 3.7.420.1 to 3.7.421.1

Bumps [AWSSDK.EC2](https://github.com/aws/aws-sdk-net) from 3.7.420.1 to 3.7.421.1.
- [Release notes](https://github.com/aws/aws-sdk-net/releases)
- [Changelog](https://github.com/aws/aws-sdk-net/blob/main/SDK.CHANGELOG.MD)
- [Commits](https://github.com/aws/aws-sdk-net/commits)

---
updated-dependencies:
- dependency-name: AWSSDK.EC2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

ServiceMonitor.AWS/ServiceMonitor.AWS.csproj

@@ -6,7 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="AWSSDK.AppRunner" Version="3.7.400.58" />
-    <PackageReference Include="AWSSDK.EC2" Version="3.7.420.1" />
+    <PackageReference Include="AWSSDK.EC2" Version="3.7.421.1" />
     <PackageReference Include="AWSSDK.ECR" Version="3.7.404.36" />
     <PackageReference Include="AWSSDK.Lambda" Version="3.7.411.1" />
     <PackageReference Include="AWSSDK.S3" Version="3.7.407.1" />