message: Add libxkbcommon to INSTALL.md dependencies
  Fixes
diff: @@ -91,7 +91,7 @@ On Arch Linux, you need a few extra libraries to build Alacritty. Here's a
  to be missing, please open an issue.
  ```sh
  -pacman -S cmake freetype2 fontconfig pkg-config make libxcb
  +pacman -S cmake freetype2 fontconfig pkg-config make libxcb libxkbcommon
  ```
  #### Fedora
  @@ -101,7 +101,7 @@ 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 libxcb-devel g++
  +dnf install cmake freetype-devel fontconfig-devel libxcb-devel libxkbcommon-devel g++
  ```
  #### CentOS/RHEL 7
  @@ -111,7 +111,7 @@ command that should install all of them. If something is still found to be
  missing, please open an issue.
  ```sh
  -yum install cmake freetype-devel fontconfig-devel libxcb-devel xcb-util-devel
  +yum install cmake freetype-devel fontconfig-devel libxcb-devel libxkbcommon-devel xcb-util-devel
  yum group install "Development Tools"
  ```
  