Bump Microsoft.Graph from 4.15.0 to 4.16.0

Bumps [Microsoft.Graph](https://github.com/microsoftgraph/msgraph-sdk-dotnet) from 4.15.0 to 4.16.0.
- [Release notes](https://github.com/microsoftgraph/msgraph-sdk-dotnet/releases)
- [Commits](microsoftgraph/msgraph-sdk-dotnet@4.15.0...4.16.0)

---
updated-dependencies:
- dependency-name: Microsoft.Graph
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/FluentEmail.Graph/FluentEmail.Graph.csproj

@@ -41,7 +41,7 @@
     <PackageReference Include="JetBrains.Annotations" Version="2021.3.0">
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.Graph" Version="4.15.0" />
+    <PackageReference Include="Microsoft.Graph" Version="4.16.0" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>