Bump Azure.Storage.Files.Shares in /src/StorageLibrary

Bumps [Azure.Storage.Files.Shares](https://github.com/Azure/azure-sdk-for-net) from 12.20.1 to 12.21.0.
- [Release notes](https://github.com/Azure/azure-sdk-for-net/releases)
- [Commits](Azure/azure-sdk-for-net@Azure.Storage.Files.Shares_12.20.1...Azure.Storage.Files.Shares_12.21.0)

---
updated-dependencies:
- dependency-name: Azure.Storage.Files.Shares
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/StorageLibrary/StorageLibrary.csproj

@@ -11,7 +11,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Data.Services.Client" Version="5.8.5" />
-    <PackageReference Include="Azure.Storage.Files.Shares" Version="12.20.1" />
+    <PackageReference Include="Azure.Storage.Files.Shares" Version="12.21.0" />
     <PackageReference Include="Azure.Storage.Blobs" Version="12.22.2" />
     <PackageReference Include="Azure.Storage.Queues" Version="12.20.1" />
     <PackageReference Include="Azure.Data.Tables" Version="12.9.1" />