[release/7.0] Bump Microsoft.Data.SqlClient to 5.1.1 (#31286)

Bump Microsoft.Data.SqlClient to 5.1.1, because the current version (5.0.2) has an insecure dependency and has not been patched because it is going out of support. (We should not have taken a dependency on a non-LTS SqlClient even in a non-LTS EF, since their support still ends before ours. Going forward, we will only ever depend on LTS SqlClient.

Ensures customers get a secure release of SqlClient by default.

Security issue in dependency.

No.

Existing tests

The reason this isn’t just a tell-mode update is that we have to jump to a new _minor_ version of SqlClient in a _patch_ release. This has some risk, but the 5.1.1 version has been out for four months now, and looks solid.

src/EFCore.SqlServer/EFCore.SqlServer.csproj

@@ -48,7 +48,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Data.SqlClient" Version="5.0.2" />
+    <PackageReference Include="Microsoft.Data.SqlClient" Version="5.1.1" />
   </ItemGroup>
 
   <ItemGroup>