message: Update Fedora and Ubuntu/Debian dependencies
diff: @@ -71,7 +71,7 @@ libraries to build Alacritty. Here's an apt command that should install all of
  them. If something is still found to be missing, please open an issue.
  ```sh
  -apt-get install cmake pkg-config libfreetype6-dev libfontconfig1-dev
  +apt-get install cmake pkg-config libfreetype6-dev libfontconfig1-dev libxcb-xfixes0-dev
  ```
  #### Arch Linux
  @@ -91,7 +91,7 @@ command that should install all of them. If something is still found to be
  missing, please open an issue.
  ```sh
  -dnf install cmake freetype-devel fontconfig-devel
  +dnf install cmake freetype-devel fontconfig-devel libxcb-devel
  ```
  #### CentOS/RHEL 7
  