chore: Rename master branch to main (#479)

Author: manosim

README.md

@@ -46,9 +46,9 @@ To run the **electron app**:
 The release process is automated. Follow the steps below.
 
 1. Create a [new **draft** release](https://github.com/manosim/gitify/releases/new). Set the tag version to something with the format of `v1.2.3`. Save as a **draft**.
-2. Once everything is merged to `master`, create a branch that starts with `release/vX.X.X` (ie. `release/v1.2.3`).
+2. Once everything is merged to `main`, create a branch that starts with `release/vX.X.X` (ie. `release/v1.2.3`).
 3. In the same branch, **bump the version** of the app in the `package.json` file and open a PR. GitHub Actions will build, sign and upload the release assets for each commit to that branch as long as a branch is named like `release/vX.X.X` and there is a draft release with the same version number(`package.json`).
-4. Merge your release branch into `master`.
+4. Merge your release branch into `main`.
 5. Publish the draft release once you've added notes to it and all assets are there.
 
 ### Tests
@@ -91,7 +91,7 @@ Gitify is licensed under the MIT Open Source license. For more information, see
 
 [github-image]: https://github.com/manosim/gitify/workflows/CI/badge.svg
 [github-url]: https://github.com/manosim/gitify/actions
-[codecov-image]: https://codecov.io/gh/manosim/gitify/branch/master/graph/badge.svg
+[codecov-image]: https://codecov.io/gh/manosim/gitify/branch/main/graph/badge.svg
 [codecov-url]: https://codecov.io/gh/manosim/gitify
 [downloads-image]: https://img.shields.io/github/downloads/manosim/gitify/total.svg
 [downloads-url]: https://www.gitify.io