Bump System.Memory from 4.5.4 to 4.5.5 (lduchosal#206)

Bumps [System.Memory](https://github.com/dotnet/corefx) from 4.5.4 to 4.5.5.
- [Release notes](https://github.com/dotnet/corefx/releases)
- [Commits](https://github.com/dotnet/corefx/commits)

---
updated-dependencies:
- dependency-name: System.Memory
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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

src/System.Net.IPNetwork/System.Net.IPNetwork.csproj

@@ -50,37 +50,37 @@
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.6'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.1'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net45'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net47'">
     <PackageReference Include="System.Memory">
-      <Version>4.5.4</Version>
+      <Version>4.5.5</Version>
     </PackageReference>
   </ItemGroup>
 </Project>