Update default branch name in README

README.md

@@ -15,7 +15,7 @@ This repository includes the thermal and electtrical sectors of prosumer model f
     - [Executing Prosumer Model](#executing-prosumer-model)
   - [Contribution Guidelines](#contribution-guidelines)
     - [Branches](#branches)
-    - [Mergen into master branch](#mergen-into-master-branch)
+    - [Merge into main branch](#merge-into-main-branch)
     - [Environment File](#environment-file)
     - [Modeling Language](#modeling-language)
     - [Programming guidelines](#programming-guidelines)
@@ -100,20 +100,20 @@ python3 runme.py
 If you want to contribute to the prosumer model, please follow the rules and guidelines specified below:
 ### Branches
 - All developing works should be done in personal branchs or feature branches. Please follow the name guidelines for creating new branches: `dev_<NameAbbr>` or `dev_<feature>`.
-- Merge requests to the `master` branch should be coordinated with other developers in advance.
-- The master branch will be updated at least every two weeks.
+- Merge requests to the `main` branch should be coordinated with other developers in advance.
+- The main branch will be updated at least every two weeks.
 
-### Mergen into master branch
-For the update process (mergen) of master branch, the following instruction in 7 Steps has been presented and should be followed:
+### Merge into main branch
+For the update process (mergen) of main branch, the following instruction in 7 Steps has been presented and should be followed:
 | Step | discription |
 | ------ | ------ |
-| Step 1 | pull master branch (remote) |
-| Step 2 | merge master branch (local) in MyFeature branch (local) and solve merge-conflicts in MyFeature branch |
+| Step 1 | pull main branch (remote) |
+| Step 2 | merge main branch (local) in MyFeature branch (local) and solve merge-conflicts in MyFeature branch |
 | Step 3 | test the MyFeature branch (local) by its functionality |
-| Step 4 | merge MyFeature branch (local) in master branch (local) |
-| Step 5 | test the master branch (local) by its functionality |
+| Step 4 | merge MyFeature branch (local) in main branch (local) |
+| Step 5 | test the main branch (local) by its functionality |
 | Step 6 | commit MyFeature branch (local) and push MyFeature branch to remote |
-| Step 7 | submit a merge request from MyFeature branch (remote) to master branch (remote) |
+| Step 7 | submit a merge request from MyFeature branch (remote) to main branch (remote) |
 
 Importance:
  - On principle, only functional codes can be merged. If this is not the case, put WIP (Work in progress) in the title of merge request.
@@ -121,7 +121,7 @@ Importance:
  - Always use merge request to update work, so that the working history is tracable.
 
 ### Environment File
-- The environment file in the `master` branch should always be synchronized with the program and should be updated simultaneously with other files.
+- The environment file in the `main` branch should always be synchronized with the program and should be updated simultaneously with other files.
 - In order to keep the used third-party packages in a reasonable size, it is necessary to stay conservative when adding new packages.
 
 ### Modeling Language