Update changelog

CHANGELOG.md

@@ -1,3 +1,19 @@
+# Changelog
+
+## v2.0.0
+
+All-You-Ever-Wanted release! :tada:
+
+- Key and salt are not required anymore. When key or salt is not specified, signature checking is disabled;
+- [New advanced URL format](./docs/generating_the_url_advanced.md). Unleash full power of imgproxy v2.0;
+- [Presets](./docs/presets.md), Shorten your urls by reusing processing options;
+- [Serving images from Amazon S3](./docs/serving_files_from_s3.md). Thanks to [@crohr](https://github.com/crohr), now we have a way to serve files from private S3 buckets;
+- [Autoconverting to WebP when supported by browser](./docs/configuration.md#webp-support-detection) (disabled by default); Use WebP as resulting format when browser supports it;
+- [Gaussian blur](./docs/generating_the_url_advanced.md#blur) and [sharpen](./docs/generating_the_url_advanced.md#sharpen) filters. Make your images look better than before;
+- [Focus point gravity](./docs/generating_the_url_advanced.md#gravity). Tell imgproxy what point will be the center of the image;
+- [Background color](./docs/generating_the_url_advanced.md#background). Control the color of background when converting PNG with alpha-channel to JPEG;
+- Calc resulting width/height automaticly when one specified as zero.
+
 ## v1.1.8
 
 - Disabled libvips cache to prevent SIGSEGV on Alpine