fix(docs): heading levels

README.md

@@ -1,6 +1,9 @@
 ![Test](https://github.com/nolimits4web/swiper/workflows/Test/badge.svg) [![jsDelivr Hits](https://data.jsdelivr.com/v1/package/npm/swiper/badge?style=rounded)](https://www.jsdelivr.com/package/npm/swiper)
+
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
+
 [![All Contributors](https://img.shields.io/badge/all_contributors-172-orange.svg?style=flat-square)](#contributors-)
+
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 <a href="https://opencollective.com/swiper/" target="_blank">
@@ -13,15 +16,15 @@ Swiper - is the free and most modern mobile touch slider with hardware accelerat
 
 Swiper is not compatible with all platforms, it is a modern touch slider which is focused only on modern apps/platforms to bring the best experience and simplicity.
 
-# Getting Started
+## Getting Started
 
 - [Getting Started Guide](https://swiperjs.com/get-started/)
 
 - [API](https://swiperjs.com/swiper-api/)
 
 - [Demos](https://swiperjs.com/demos/)
 
-# Dist / Build
+## Dist / Build
 
 On production use files (JS and CSS) only from `package/` folder, there will be the most stable versions, `build/` folder is only for development purpose.
 
@@ -87,11 +90,11 @@ $ npm run build:prod
 
 Production version will available in `package/` folder.
 
-# Contributing
+## Contributing
 
 All changes should be committed to `src/` files only. Before you open an issue please review the [contributing](https://github.com/nolimits4web/swiper/blob/master/CONTRIBUTING.md) guideline.
 
-# Swiper 5.x
+## Swiper 5.x
 
 If you are still using Swiper 5.x.x, you may find it in [Swiper5 Branch](https://github.com/nolimits4web/swiper/tree/Swiper5)
 
@@ -101,7 +104,7 @@ If you are still using Swiper 5.x.x, you may find it in [Swiper5 Branch](https:/
 
 - [API](https://github.com/nolimits4web/swiper/blob/Swiper5/API.md)
 
-# Swiper 4.x
+## Swiper 4.x
 
 If you are still using Swiper 4.x.x, you may find it in [Swiper4 Branch](https://github.com/nolimits4web/swiper/tree/Swiper4)
 
@@ -111,7 +114,7 @@ If you are still using Swiper 4.x.x, you may find it in [Swiper4 Branch](https:/
 
 - [API](https://github.com/nolimits4web/swiper/blob/Swiper4/API.md)
 
-# Swiper 3.x
+## Swiper 3.x
 
 If you are still using Swiper 3.x.x, you may find it in [Swiper3 Branch](https://github.com/nolimits4web/swiper/tree/Swiper3)
 
@@ -121,7 +124,7 @@ If you are still using Swiper 3.x.x, you may find it in [Swiper3 Branch](https:/
 
 - [API](https://github.com/nolimits4web/swiper/blob/Swiper3/API.md)
 
-# Swiper 2.x
+## Swiper 2.x
 
 If you are still using Swiper 2.x.x or you need old browsers support, you may find it in [Swiper2 Branch](https://github.com/nolimits4web/swiper/tree/Swiper2)
 
@@ -368,4 +371,4 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
-This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!