Release v2.1.0 - Modo (모도, 茅島)

Object split and deletion improvements, documentation clarifications.

Signed-off-by: Stanislav Bogatyrev <stanislav@nspcc.ru>

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## [2.1.0] - 2020-12-XX - Modo (모도, 茅島)
+## [2.1.0] - 2020-12-11 - Modo (모도, 茅島)
 
 Object split and deletion improvements, documentation clarifications.
 

CONTRIBUTING.md

@@ -25,7 +25,7 @@ Start by forking the `neofs-api` repository, make changes in a branch and then
 send a pull request. We encourage pull requests to discuss code changes. Here
 are the steps in details:
 
-### Setup your GitHub Repository
+### Set up your GitHub Repository
 Fork [NeoFS node upstream](https://github.com/nspcc-dev/neofs-api/fork) source
 repository to your own personal repository. Copy the URL of your fork (you will
 need it for the `git clone` command below).
@@ -48,7 +48,7 @@ Before making code changes, make sure you create a separate branch for these
 changes. Maybe you will find it convenient to name branch in
 `<type>/<Issue>-<changes_topic>` format.
 
-```
+```sh
 $ git checkout -b feature/123-something_awesome
 ```
 
@@ -75,7 +75,7 @@ Description
 <Sign-Off>
 ```
 
-```
+```sh
 $ git commit -am '[#123] Add some feature'
 ```
 
@@ -109,7 +109,7 @@ Signed-off-by: Samii Sakisaka <samii@nspcc.ru>
 This can easily be done with the `--signoff` option to `git commit`.
 
 By doing this you state that you can certify the following (from [The Developer
-Certificate of Origin](https://developercertificate.org/):
+Certificate of Origin](https://developercertificate.org/)):
 
 ```
 Developer Certificate of Origin

README.md

@@ -29,7 +29,7 @@ This repository contains:
 Feel free to contribute to this project after reading the [contributing
 guidelines](CONTRIBUTING.md).
 
-Before starting to work on a certain topic, create an new issue first,
+Before starting to work on a certain topic, create a new issue first,
 describing the feature/topic you are going to implement.
 
 ## License