[#511] docs: Remove GitHub mentions from CONTRIBUTING.md

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

CONTRIBUTING.md

@@ -3,8 +3,8 @@
 First, thank you for contributing! We love and encourage pull requests from
 everyone. Please follow the guidelines:
 
-- Check the open [issues](https://github.com/TrueCloudLab/frostfs-node/issues) and
-  [pull requests](https://github.com/TrueCloudLab/frostfs-node/pulls) for existing
+- Check the open [issues](https://git.frostfs.info/TrueCloudLab/frostfs-node/issues) and
+  [pull requests](https://git.frostfs.info/TrueCloudLab/frostfs-node/pulls) for existing
   discussions.
 
 - Open an issue first, to discuss a new feature or enhancement.
@@ -27,19 +27,19 @@ Start by forking the `frostfs-node` repository, make changes in a branch and the
 send a pull request. We encourage pull requests to discuss code changes. Here
 are the steps in details:
 
-### Set up your GitHub Repository
-Fork [FrostFS node upstream](https://github.com/TrueCloudLab/frostfs-node/fork) source
+### Set up your Forgejo repository
+Fork [FrostFS node upstream](https://git.frostfs.info/TrueCloudLab/frostfs-node) source
 repository to your own personal repository. Copy the URL of your fork (you will
 need it for the `git clone` command below).
 
 ```sh
-$ git clone https://github.com/TrueCloudLab/frostfs-node
+$ git clone https://git.frostfs.info/TrueCloudLab/frostfs-node
 ```
 
 ### Set up git remote as ``upstream``
 ```sh
 $ cd frostfs-node
-$ git remote add upstream https://github.com/TrueCloudLab/frostfs-node
+$ git remote add upstream https://git.frostfs.info/TrueCloudLab/frostfs-node
 $ git fetch upstream
 $ git merge upstream/master
 ...
@@ -58,7 +58,7 @@ $ git checkout -b feature/123-something_awesome
 After your code changes, make sure
 
 - To add test cases for the new code.
-- To run `make lint`
+- To run `make lint` and `make staticcheck-run`
 - To squash your commits into a single commit or a series of logically separated
   commits run `git rebase -i`. It's okay to force update your pull request.
 - To run `make test` and `make all` completes.
@@ -89,8 +89,8 @@ $ git push origin feature/123-something_awesome
 ```
 
 ### Create a Pull Request
-Pull requests can be created via GitHub. Refer to [this
-document](https://help.github.com/articles/creating-a-pull-request/) for
+Pull requests can be created via Forgejo. Refer to [this
+document](https://docs.codeberg.org/collaborating/pull-requests-and-git-flow/) for
 detailed steps on how to create a pull request. After a Pull Request gets peer
 reviewed and approved, it will be merged.