Rename 'master' branch to 'main'

See https://github.com/github/renaming for details on the rationale

Author: sfeilmeier

README.md

@@ -1,5 +1,5 @@
 [![Build Status](https://github.com/OpenEMS/openems/actions/workflows/build.yml/badge.svg)](https://github.com/OpenEMS/openems/actions/workflows/build.yml)
-[![Gitpod live-demo](https://img.shields.io/badge/Gitpod-live--demo-blue?logo=gitpod)](https://gitpod.io/#https://github.com/OpenEMS/openems/tree/master)
+[![Gitpod live-demo](https://img.shields.io/badge/Gitpod-live--demo-blue?logo=gitpod)](https://gitpod.io/#https://github.com/OpenEMS/openems/tree/main)
 [![Cite via Zenodo](https://zenodo.org/badge/DOI/10.5281/zenodo.4440884.svg)](https://doi.org/10.5281/zenodo.4440883)
 
 <h1 align="center">

doc/modules/ROOT/pages/gettingstarted.adoc

@@ -315,7 +315,7 @@ NOTE: The *Metadata* service provider is responsible for authentication of Edge
 .Configuration of Backend Metadata.Dummy
 image::config-backend-metadata.dummy.png[Configuration of Backend Metadata.Dummy]
 +
-NOTE: In the example we are configuring the _**Metadata.Dummy**_ service. It takes no configuration parameters, so just press btn:[Save]. In a production system you would want to use a real implementation like _**Metadata.File**_, which uses a static JSON file as input, or _**Metadata.Odoo**_, which uses the *Odoo* business software for authentication and IoT device management. This will require the https://github.com/OpenEMS/odoo-openems[Odoo-OpenEMS-Addon] to be installed on your Odoo instance. See the https://gitpod.io/#https://github.com/OpenEMS/openems/tree/master[OpenEMS Live-Demo Gitpod workspace] for a full, production ready example configuration. For more information see → xref:simulation/gitpod.adoc[Gitpod Workspace]
+NOTE: In the example we are configuring the _**Metadata.Dummy**_ service. It takes no configuration parameters, so just press btn:[Save]. In a production system you would want to use a real implementation like _**Metadata.File**_, which uses a static JSON file as input, or _**Metadata.Odoo**_, which uses the *Odoo* business software for authentication and IoT device management. This will require the https://github.com/OpenEMS/odoo-openems[Odoo-OpenEMS-Addon] to be installed on your Odoo instance. See the https://gitpod.io/#https://github.com/OpenEMS/openems/tree/main[OpenEMS Live-Demo Gitpod workspace] for a full, production ready example configuration. For more information see → xref:simulation/gitpod.adoc[Gitpod Workspace]
 
 === Configure OpenEMS Edge
 

doc/modules/ROOT/pages/introduction.adoc

@@ -51,7 +51,7 @@ image::system-architecture.png[OpenEMS system architecture]
 The source code is available online at https://openems.io[openems.io] and on https://github.com/OpenEMS/openems[GitHub icon:github[]]. 
 New versions are released every month and https://github.com/OpenEMS/openems/releases[tagged icon:github[]] accordingly. 
 Version numbers are built using the pattern `year.month.0`, e.g. version `2022.1.0` is the release of January 2022. The patch version is always `0` and reserved for private distributions.  
-Git development follows the https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow[Gitflow Workflow], so the https://github.com/OpenEMS/openems/tree/master/[master branch icon:github[]] always holds the stable release, while active development is happening on the https://github.com/OpenEMS/openems/tree/develop[develop branch icon:github[]] or in separate feature branches.
+Git development follows the https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow[Gitflow Workflow], so the https://github.com/OpenEMS/openems/tree/main/[main branch icon:github[]] always holds the stable release, while active development is happening on the https://github.com/OpenEMS/openems/tree/develop[develop branch icon:github[]] or in separate feature branches.
 
 For Edge and Backend Java development we recommend the https://www.eclipse.org/ide/[Eclipse IDE icon:external-link[]].
 For the UI (TypeScript + Angular.io) we recommend https://code.visualstudio.com/[Visual Studio Code icon:external-link[]].