chore: Setup semantic releases on master (#71)

This brings back semantic releases from master branch. Let's keep it this way, until we can think of a better release/deploy process.

Author: Krzysztof Borowy

.circleci/config.yml

@@ -318,4 +318,4 @@ workflows:
             - "Test: iOS e2e"
           filters:
             branches:
-              only: release
+              only: master

.releaserc

@@ -1,5 +1,5 @@
 {
-  "branch": "release",
+  "branch": "master",
   "plugins": [
     "@semantic-release/commit-analyzer",
     "@semantic-release/release-notes-generator",

CONTRIBUTING.md

@@ -23,7 +23,7 @@ When you're sending a pull request:
 
 
 ## Commits and versioning
-All PRs are squashed into `release` branch and wrapped up in a single commit, following [conventional commit message](https://www.conventionalcommits.org/en/v1.0.0-beta.3). Combined with [semantic versioning](https://semver.org/), this allows us to have a frequent releases of the library.
+All PRs are squashed into `master` branch and wrapped up in a single commit, following [conventional commit message](https://www.conventionalcommits.org/en/v1.0.0-beta.3). Combined with [semantic versioning](https://semver.org/), this allows us to have a frequent releases of the library.
 
 *Note*: We don't force this convention on Pull Requests from contributors, but it's a clean way to see what type of changes are made, so feel free to follow it. 
 
@@ -40,11 +40,11 @@ Most notably prefixes you'll see:
 
 
 ## Release process
-We use [Semantic Release](http://semantic-release.org) to automatically release new versions of the library when changes are merged into `release` branch. We plan to keep the `master` stable, before cutting the new versions. Bugs fixes take priority in release order.
+We use [Semantic Release](http://semantic-release.org) to automatically release new versions of the library when changes are merged into `master` branch, which we plan to keep stable. Bug fixes take priority in the release order.
 
 ## Reporting issues
 You can report issues on our [bug tracker](https://github.com/react-native-community/react-native-async-storage/issues). Please search for existing issues and follow the issue template when opening an one.
 
 
 ## License
-By contributing to React Native Async Storage, you agree that your contributions will be licensed under the **MIT** license.
+By contributing to React Native Async Storage, you agree that your contributions will be licensed under the **MIT** license.