replace "master" with "main"

As "main" has become the preferred term for the name of that branch, this document should reflect that as well. The various independent translations should follow the same practice.

Author: AspenForester

README.md

@@ -68,18 +68,18 @@ request.
  Use the following naming convention:
 
  ```shell
- $ git checkout -b feature-a/master # team-wide branch
+ $ git checkout -b feature-a/main # team-wide branch
  $ git checkout -b feature-a/maria # Maria's personal branch
  $ git checkout -b feature-a/nick # Nick's personal branch
  ```
 
  Merge at will the personal branches to the team-wide branch (see ["Merging"](#merging)).
- Eventually, the team-wide branch will be merged to "master".
+ Eventually, the team-wide branch will be merged to "main".
 
 * Delete your branch from the upstream repository after it's merged, unless
  there is a specific reason not to.
 
- Tip: Use the following command while being on "master", to list merged
+ Tip: Use the following command while being on "main", to list merged
  branches:
 
  ```shell
@@ -209,9 +209,9 @@ holds true that you should apply all of the above *before* pushing it.
  * You are the only one working on the branch and it is not being reviewed.
 
  * You want to tidy up your branch (eg. squash commits) and/or rebase it onto
- the "master" in order to merge it later.
+ the "main" in order to merge it later.
 
- That said, *never rewrite the history of the "master" branch* or any other
+ That said, *never rewrite the history of the "main" branch* or any other
  special branches (ie. used by production or CI servers).
 
 * Keep the history *clean* and *simple*. *Just before you merge* your branch:
@@ -223,16 +223,16 @@ holds true that you should apply all of the above *before* pushing it.
 
  ```shell
  [my-branch] $ git fetch
- [my-branch] $ git rebase origin/master
+ [my-branch] $ git rebase origin/main
  # then merge
  ```
 
  This results in a branch that can be applied directly to the end of the
- "master" branch and results in a very simple history.
+ "main" branch and results in a very simple history.
 
  *(Note: This strategy is better suited for projects with short-running
  branches. Otherwise it might be better to occassionally merge the
- "master" branch instead of rebasing onto it.)*
+ "main" branch instead of rebasing onto it.)*
 
 * If your branch includes more than one commit, do not merge with a
  fast-forward: