Removed archlinux from build (it doesn't work anymore

CONTRIBUTING.md

@@ -9,6 +9,7 @@ Please note we have a [code of conduct](CODE_OF_CONDUCT.md), please follow it in
   - [Developer contributions guide](#developer-contributions-guide)
     - [How TermSCP works](#how-termscp-works)
       - [Activities](#activities)
+    - [Tests fails due to receivers](#tests-fails-due-to-receivers)
     - [Implementing File Transfers](#implementing-file-transfers)
 
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@@ -65,6 +66,12 @@ This trait provides only 3 methods:
 
 ---
 
+### Tests fails due to receivers
+
+Yes. This happens quite often and is related to the fact that I'm using public SSH/SFTP/FTP server to test file receivers and sometimes this server go down for even a day or more. If your tests don't pass due to this, don't worry, submit the pull request and I'll take care of testing them by myself.
+
+---
+
 ### Implementing File Transfers
 
 This chapter describes how to implement a file transfer in TermSCP. A file transfer is a module which implements the `FileTransfer` trait. The file transfer provides different modules to interact with a remote server, which in addition to the most obvious methods, used to download and upload files, provides also methods to list files, delete files, create directories etc.