Bump DocumentFormat.OpenXml from 2.15.0 to 2.16.0

Bumps [DocumentFormat.OpenXml](https://github.com/OfficeDev/Open-XML-SDK) from 2.15.0 to 2.16.0.
- [Release notes](https://github.com/OfficeDev/Open-XML-SDK/releases)
- [Changelog](https://github.com/OfficeDev/Open-XML-SDK/blob/main/CHANGELOG.md)
- [Commits](dotnet/Open-XML-SDK@v2.15.0...v2.16.0)

---
updated-dependencies:
- dependency-name: DocumentFormat.OpenXml
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

OpenXmlPowerTools/OpenXmlPowerTools.csproj

@@ -43,7 +43,7 @@
 		<None Remove="Properties\**" />
 	</ItemGroup>
 	<ItemGroup>
-		<PackageReference Include="DocumentFormat.OpenXml" Version="2.15.0" />
+		<PackageReference Include="DocumentFormat.OpenXml" Version="2.16.0" />
 		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1">
 			<PrivateAssets>all</PrivateAssets>
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>