chore: change the dependency from the ESDK to the MPL to a relative path ProjectReference (#656)

Author: rishav-karanjit

AwsEncryptionSDK/runtimes/net/ESDK.csproj

@@ -33,7 +33,7 @@
       <PackageReference Include="AWSSDK.Core" Version="3.7.300.2" />
       <PackageReference Include="DafnyRuntime" Version="4.2.0" />
       <PackageReference Include="BouncyCastle.Cryptography" Version="2.2.1" />
-      <PackageReference Include="AWS.Cryptography.MaterialProviders" Version="1.3.0" />
+      <ProjectReference Include="../../../mpl/AwsCryptographicMaterialProviders/runtimes/net/MPL.csproj" />
       <!--
         System.Collections.Immutable can be removed once dafny.msbuild is updated with
         https://github.com/dafny-lang/dafny.msbuild/pull/10 and versioned