Update README

- Switch MyGet badges to Azure Artifacts.
- Improve style of several badges.
- Fix markdown style.

Signed-off-by: José Simões <jose.simoes@eclo.solutions>

Author: josesimoes

README.md

@@ -1,39 +1,34 @@
-[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=nanoframework_lib-CoreLibrary&metric=alert_status)](https://sonarcloud.io/dashboard?id=nanoframework_lib-CoreLibrary) [![Reliability Rating](https://sonarcloud.io/api/project_badges/measure?project=nanoframework_lib-CoreLibrary&metric=reliability_rating)](https://sonarcloud.io/dashboard?id=nanoframework_lib-CoreLibrary) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://github.com/nanoframework/Home/blob/master/LICENSE) [![NuGet](https://img.shields.io/nuget/dt/nanoFramework.CoreLibrary.svg)]() [![#yourfirstpr](https://img.shields.io/badge/first--timers--only-friendly-blue.svg)](https://github.com/nanoframework/Home/blob/master/CONTRIBUTING.md)
-[![Discord](https://img.shields.io/discord/478725473862549535.svg)](https://discord.gg/gCyBu8T)
-
+[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=nanoframework_lib-CoreLibrary&metric=alert_status)](https://sonarcloud.io/dashboard?id=nanoframework_lib-CoreLibrary) [![Reliability Rating](https://sonarcloud.io/api/project_badges/measure?project=nanoframework_lib-CoreLibrary&metric=reliability_rating)](https://sonarcloud.io/dashboard?id=nanoframework_lib-CoreLibrary) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://github.com/nanoframework/Home/blob/master/LICENSE) [![NuGet](https://img.shields.io/nuget/dt/nanoFramework.CoreLibrary.svg?label=NuGet&style=flat&logo=nuget)](https://www.nuget.org/packages/nanoFramework.CoreLibrary/) [![#yourfirstpr](https://img.shields.io/badge/first--timers--only-friendly-blue.svg)](https://github.com/nanoframework/Home/blob/master/CONTRIBUTING.md)
+[![Discord](https://img.shields.io/discord/478725473862549535.svg?logo=discord&logoColor=white&label=Discord&color=7289DA)](https://discord.gg/gCyBu8T)
 
 ![nanoFramework logo](https://github.com/nanoframework/Home/blob/master/resources/logo/nanoFramework-repo-logo.png)
 
 -----
 
 ### Welcome to the **nanoFramework** Core Library repository!
 
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 ## Build status
 
 | Component | Build Status | NuGet Package |
 |:-|---|---|
-| Core Library | [![Build Status](https://dev.azure.com/nanoframework/CoreLibrary/_apis/build/status/nanoframework.lib-CoreLibrary?branchName=develop)](https://dev.azure.com/nanoframework/CoreLibrary/_build/latest?definitionId=24?branchName=master) | [![NuGet](https://img.shields.io/nuget/v/nanoFramework.CoreLibrary.svg)](https://www.nuget.org/packages/nanoFramework.CoreLibrary/)  |
-| Core Library (preview) | [![Build Status](https://dev.azure.com/nanoframework/CoreLibrary/_apis/build/status/nanoframework.lib-CoreLibrary?branchName=develop)](https://dev.azure.com/nanoframework/CoreLibrary/_build/latest?definitionId=24?branchName=develop) | [![MyGet Pre Release](https://img.shields.io/myget/nanoframework-dev/vpre/nanoFramework.CoreLibrary.svg)](https://www.myget.org/feed/nanoframework-dev/package/nuget/nanoFramework.CoreLibrary) |
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+| Core Library | [![Build Status](https://dev.azure.com/nanoframework/CoreLibrary/_apis/build/status/nanoframework.lib-CoreLibrary?branchName=develop)](https://dev.azure.com/nanoframework/CoreLibrary/_build/latest?definitionId=24?branchName=master) | [![NuGet](https://img.shields.io/nuget/v/nanoFramework.CoreLibrary.svg?label=NuGet&style=flat&logo=nuget)](https://www.nuget.org/packages/nanoFramework.CoreLibrary/)  |
+| Core Library (preview) | [![Build Status](https://dev.azure.com/nanoframework/CoreLibrary/_apis/build/status/nanoframework.lib-CoreLibrary?branchName=develop)](https://dev.azure.com/nanoframework/CoreLibrary/_build/latest?definitionId=24?branchName=develop) | [![](https://badgen.net/badge/NuGet/preview/D7B023?icon=https://simpleicons.now.sh/azuredevops/fff)](https://dev.azure.com/nanoframework/feed/_packaging?_a=package&feed=sandbox&package=nanoFramework.CoreLibrary&protocolType=NuGet&view=overview) |
 
 ## Feedback and documentation
 
 For documentation, providing feedback, issues and finding out how to contribute please refer to the [Home repo](https://github.com/nanoframework/Home).
 
 Join our Discord community [here](https://discord.gg/gCyBu8T).
 
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 ## Credits
 
 The list of contributors to this project can be found at [CONTRIBUTORS](https://github.com/nanoframework/Home/blob/master/CONTRIBUTORS.md).
 
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 ## License
 
 The **nanoFramework** Class Libraries are licensed under the [Apache 2.0 license](http://www.apache.org/licenses/LICENSE-2.0).
 
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 ## Code of Conduct
+
 This project has adopted the code of conduct defined by the [Contributor Covenant](http://contributor-covenant.org/)
 to clarify expected behavior in our community.