address norm's comments

Author: philasmar

CONTRIBUTING.md

@@ -39,6 +39,45 @@ To send us a pull request, please:
 GitHub provides additional document on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).
 
+## Adding a `change file` to your contribution branch
+
+Each contribution branch should include a `change file` that contains a changelog message for each project that has been updated, as well as the type of increment to perform for those changes when versioning the project.
+
+A `change file` looks like the following example:
+```json
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Extensions.S3.Encryption",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Fixed an issue causing a failure somewhere"
+      ]
+    }
+  ]
+}
+```
+The `change file` lists all the modified projects, the changelog message for each project as well as the increment type. 
+
+These files are located in the repo at .autover/changes/
+
+You can use the `AutoVer` tool to create the change file. You can install it using the following command:
+```
+dotnet tool install -g AutoVer
+```
+
+You can create the `change file` using the following command:
+```
+autover change -m "Fixed an issue causing a failure somewhere"
+```
+Note: Make sure to run the command from the root of the repository.
+
+The possible increment types are:
+* Patch
+* Minor
+* Major
+
+Note: You do not need to create a new `change file` for every changelog message or project within your branch. You can create one `change file` that contains all the modified projects and the changelog messages.
 
 ## Finding contributions to work on
 Looking at the existing issues is a great way to find something to contribute on. As our projects, by default, use the default GitHub issue labels (enhancement/bug/duplicate/help wanted/invalid/question/wontfix), looking at any 'help wanted' issues is a great place to start.

src/Amazon.Extensions.S3.Encryption.csproj

@@ -18,6 +18,7 @@
         <SignAssembly>true</SignAssembly>
         <AssemblyOriginatorKeyFile>..\public.snk</AssemblyOriginatorKeyFile>
         <PackageReadmeFile>README.md</PackageReadmeFile>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     </PropertyGroup>
 
     <PropertyGroup Condition="'$(TargetFramework)' == 'net472'">
@@ -35,6 +36,10 @@
         <PackageReference Include="AWSSDK.S3" Version="4.0.0-preview.2" />
         <PackageReference Include="AWSSDK.KeyManagementService" Version="4.0.0-preview.2" />
         <PackageReference Include="BouncyCastle.Cryptography" Version="2.4.0" />
+    </ItemGroup>
+
+    <!-- TODO: The dependency on Microsoft.Bcl.AsyncInterfaces should be removed once the issue causing it to be needed in the .NET SDK is fixed  -->
+    <ItemGroup Condition="'$(TargetFramework)' == 'net472' Or '$(TargetFramework)' == 'netstandard2.0'">
         <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="8.0.0" />
     </ItemGroup>