Bump Azure.Security.KeyVault.Keys from 4.2.0 to 4.3.0

Bumps [Azure.Security.KeyVault.Keys](https://github.com/Azure/azure-sdk-for-net) from 4.2.0 to 4.3.0.
- [Release notes](https://github.com/Azure/azure-sdk-for-net/releases)
- [Commits](Azure/azure-sdk-for-net@Azure.Security.KeyVault.Keys_4.2.0...Azure.Security.KeyVault.Keys_4.3.0)

---
updated-dependencies:
- dependency-name: Azure.Security.KeyVault.Keys
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

src/HealthChecks.AzureKeyVault/HealthChecks.AzureKeyVault.csproj

@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Azure.Security.KeyVault.Certificates" Version="4.3.0" />
-    <PackageReference Include="Azure.Security.KeyVault.Keys" Version="4.2.0" />
+    <PackageReference Include="Azure.Security.KeyVault.Keys" Version="4.3.0" />
     <PackageReference Include="Azure.Security.KeyVault.Secrets" Version="4.3.0" />
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks" Version="6.0.3" />
     <PackageReference Include="Microsoft.Azure.Services.AppAuthentication" Version="1.6.2" />