update master to main

new work processes use 'main' instead of 'master'

content/github/collaborating-with-issues-and-pull-requests/syncing-a-fork.md

@@ -20,16 +20,16 @@ Before you can sync your fork with an upstream repository, you must [configure a
   > remote: Total 62 (delta 27), reused 44 (delta 9)
   > Unpacking objects: 100% (62/62), done.
   > From https://{% data variables.command_line.codeblock %}/<em>ORIGINAL_OWNER</em>/<em>ORIGINAL_REPOSITORY</em>
-  >  * [new branch]      master     -> upstream/master
+  >  * [new branch]      main     -> upstream/main
   ```
-4. Check out your fork's local `master` branch.
+4. Check out your fork's local `main` branch.
   ```shell
-  $ git checkout master
-  > Switched to branch 'master'
+  $ git checkout main
+  > Switched to branch 'https://github.com/todbot/qtpy-tricks.git'
   ```
-5. Merge the changes from `upstream/master` into your local `master` branch. This brings your fork's `master` branch into sync with the upstream repository, without losing your local changes.
+5. Merge the changes from `upstream/main` into your local `main` branch. This brings your fork's `main` branch into sync with the upstream repository, without losing your local changes.
   ```shell
-  $ git merge upstream/master
+  $ git merge upstream/main
   > Updating a422352..5fdff0f
   > Fast-forward
   >  README                    |    9 -------
@@ -39,7 +39,7 @@ Before you can sync your fork with an upstream repository, you must [configure a
   >  create mode 100644 README.md
   ``` If your local branch didn't have any unique commits, Git will instead perform a "fast-forward":
   ```shell
-  $ git merge upstream/master
+  $ git merge upstream/main
   > Updating 34e91da..16c56ad
   > Fast-forward
   >  README.md                 |    5 +++--