Removing certificate pinning code and references (#361)

* Removing certificate pinning code and references

* Fixing lint

* More linting

* Removing the cert helper fully and updated the readme

* Removing README chagnes for now

---------

Co-authored-by: Eli Iser <eiser@dropbox.com>

Author: eli-iser

dropbox-sdk-dotnet/Dropbox.Api/DropboxCertHelper.cs

@@ -56,8 +56,6 @@ static int Main(string[] args)
 
         private async Task<int> Run()
         {
-            DropboxCertHelper.InitializeCertPinning();
-
             var uid = await this.AcquireAccessToken(null, IncludeGrantedScopes.None);
             if (string.IsNullOrEmpty(uid))
             {

dropbox-sdk-dotnet/Examples/OAuthPKCE/Program.cs

@@ -59,8 +59,6 @@ static int Main(string[] args)
 
         private async Task<int> Run()
         {
-            DropboxCertHelper.InitializeCertPinning();
-
             string[] scopeList = new string[3] { "files.metadata.read", "files.content.read", "account_info.read" };
             var uid = await this.AcquireAccessToken(scopeList, IncludeGrantedScopes.None);
             if (string.IsNullOrEmpty(uid))

dropbox-sdk-dotnet/Examples/OauthBasic/Program.cs

@@ -59,8 +59,6 @@ static int Main(string[] args)
 
         private async Task<int> Run()
         {
-            DropboxCertHelper.InitializeCertPinning();
-
             var accessToken = await this.GetAccessToken();
             if (string.IsNullOrEmpty(accessToken))
             {