[TASK] Prepare the 2.0.0 release (#461)

Closes #421

CHANGELOG.md

@@ -1,10 +1,10 @@
 # Emogrifier Change Log
 
 All notable changes to this project will be documented in this file.
-This project adheres to [Semantic Versioning](http://semver.org/).
+This project adheres to [Semantic Versioning](https://semver.org/).
 
 
-## x.y.z (unreleased)
+## 2.0.0
 
 ### Added
 - Support for CSS :not() selector

Classes/Emogrifier.php

@@ -7,7 +7,7 @@
  *
  * For more information, please see the README.md file.
  *
- * @version 1.2.0
+ * @version 2.0.0
  *
  * @author Cameron Brooks
  * @author Jaime Prado

README.md

@@ -141,21 +141,21 @@ curl -s https://getcomposer.org/installer | php
 Run the following command for a local installation:
 
 ```bash
-php composer.phar require pelago/emogrifier:@dev
+php composer.phar require pelago/emogrifier:^2.0.0
 ```
 
 Or for a global installation, run the following command:
 
 ```bash
-composer require pelago/emogrifier:^1.2.0
+composer require pelago/emogrifier:^2.0.0
 ```
 
 You can also add follow lines to your `composer.json` and run the
 `composer update` command:
 
 ```json
 "require": {
-  "pelago/emogrifier": "^1.2.0"
+  "pelago/emogrifier": "^2.0.0"
 }
 ```
 
@@ -232,6 +232,24 @@ The following selectors are not implemented yet:
   cannot be converted accurately).
 
 
+## Steps to release a new version
+
+1. Create a pull request "Prepare release of version x.y.z" with the following
+   changes.
+2. Set the new version number in the `@version` annotation in the class PHPDoc
+   of [Emogrifier.php](Classes/Emogrifier.php).
+3. In the [composer.json](composer.json), update the `branch-alias` entry to
+   point to the release _after_ the upcoming release.
+4. In the [README.md](README.md), update the version numbers in the section
+   [Installing with Composer](#installing-with-composer).
+5. In the [CHANGELOG.md](CHANGELOG.md), set the version number and remove any
+   empty sections.
+6. Have the pull request reviewed and merged.
+7. In the [Releases tab](https://github.com/MyIntervals/emogrifier/releases),
+   create a new release and copy the change log entries to the new release.
+8. Post about the new release on social media.
+
+
 ## Maintainers
 
 * [Oliver Klee](https://github.com/oliverklee)

composer.json

@@ -55,7 +55,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.0.x-dev"
+            "dev-master": "2.1.x-dev"
         }
     }
 }