Bump AWSSDK.DynamoDBv2 from 3.7.3.19 to 3.7.3.20 (#1074)

Bumps [AWSSDK.DynamoDBv2](https://github.com/aws/aws-sdk-net) from 3.7.3.19 to 3.7.3.20.
- [Release notes](https://github.com/aws/aws-sdk-net/releases)
- [Commits](https://github.com/aws/aws-sdk-net/commits)

---
updated-dependencies:
- dependency-name: AWSSDK.DynamoDBv2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/HealthChecks.DynamoDb/HealthChecks.DynamoDb.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="AWSSDK.DynamoDBv2" Version="3.7.3.19" />
+    <PackageReference Include="AWSSDK.DynamoDBv2" Version="3.7.3.20" />
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks" Version="6.0.3" />
   </ItemGroup>