Bump Assent from 1.4.2 to 1.7.0 in /source

Bumps [Assent](https://github.com/droyad/Assent) from 1.4.2 to 1.7.0.
- [Release notes](https://github.com/droyad/Assent/releases)
- [Commits](droyad/Assent@1.4.2...1.7.0)

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

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

Author: dependabot[bot]

source/Server.Tests/Server.Tests.csproj

@@ -6,7 +6,7 @@
     <AssemblyName>Octopus.Server.Extensibility.JiraIntegration.Tests</AssemblyName>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Assent" Version="1.4.2" />
+    <PackageReference Include="Assent" Version="1.7.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.0.1" />
     <PackageReference Include="NSubstitute" Version="3.1.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />