docs: fixes broken links in Readme

README.md

@@ -24,7 +24,7 @@ Register your application to use Microsoft Graph API using the [Microsoft Applic
 
 The Microsoft Graph .NET Client Library supports the use of TokenCredential classes in the [Azure.Identity](https://www.nuget.org/packages/Azure.Identity) library.
 
-You can read more about available Credential classes [here](https://docs.microsoft.com/en-us/dotnet/api/overview/azure/identity-readme#key-concepts) and examples on how to quickly setup TokenCredential instances can be found [here](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/tokencredentials.md).
+You can read more about available Credential classes [here](https://docs.microsoft.com/en-us/dotnet/api/overview/azure/identity-readme#key-concepts) and examples on how to quickly setup TokenCredential instances can be found [here](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/tokencredentials.md).
 
 The recommended library for authenticating against Microsoft Identity (Azure AD) is [MSAL](https://github.com/AzureAD/microsoft-authentication-library-for-dotnet).
 
@@ -37,7 +37,7 @@ sending them to Microsoft Graph API, and processing the responses. To create a
 new instance of this class, you need to provide an instance of
 `IAuthenticationProvider` which can authenticate requests to Microsoft Graph.
 
-For more information on initializing a client instance, see the [library overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/overview.md)
+For more information on initializing a client instance, see the [library overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/overview.md)
 
 ### 4. Make requests to the graph
 
@@ -67,7 +67,7 @@ var rootItem = await graphClient.Drives[userDriveId].Root.GetAsync();
 `GetAsync` will return a `DriveItem` object on success and throw a
 `ApiException` on error.
 
-For a general overview of how the SDK is designed, see [overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/overview.md).
+For a general overview of how the SDK is designed, see [overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/overview.md).
 
 The following sample applications are also available:
 * [Microsoft Graph UWP Connect Sample](https://github.com/microsoftgraph/uwp-csharp-connect-sample)
@@ -82,10 +82,10 @@ The following sample applications are also available:
 
 ## Documentation and resources
 
-* [Overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/overview.md)
-* [Collections](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/collections.md)
-* [Errors](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/errors.md)
-* [Headers](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/headers.md)
+* [Overview](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/overview.md)
+* [Collections](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/collections.md)
+* [Errors](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/errors.md)
+* [Headers](https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/main/docs/headers.md)
 * [Microsoft Graph API](https://graph.microsoft.com)
 * [Release notes](https://github.com/microsoftgraph/msgraph-sdk-dotnet/releases)
 * [Blog - Microsoft Graph .NET SDK updates 3/16/20](https://developer.microsoft.com/en-us/graph/blogs/microsoft-graph-net-sdk-updates/)