chore(docs): Update README.md (nvim-lua#1344)

Neovim has renamed the "linux64" binary to "linux-x86_64".

Author: rnevius

README.md

@@ -219,14 +219,14 @@ sudo apt update
 sudo apt install make gcc ripgrep unzip git xclip curl
 
 # Now we install nvim
-curl -LO https://github.com/neovim/neovim/releases/latest/download/nvim-linux64.tar.gz
-sudo rm -rf /opt/nvim-linux64
-sudo mkdir -p /opt/nvim-linux64
-sudo chmod a+rX /opt/nvim-linux64
-sudo tar -C /opt -xzf nvim-linux64.tar.gz
+curl -LO https://github.com/neovim/neovim/releases/latest/download/nvim-linux-x86_64.tar.gz
+sudo rm -rf /opt/nvim-linux-x86_64
+sudo mkdir -p /opt/nvim-linux-x86_64
+sudo chmod a+rX /opt/nvim-linux-x86_64
+sudo tar -C /opt -xzf nvim-linux-x86_64.tar.gz
 
 # make it available in /usr/local/bin, distro installs to /usr/bin
-sudo ln -sf /opt/nvim-linux64/bin/nvim /usr/local/bin/
+sudo ln -sf /opt/nvim-linux-x86_64/bin/nvim /usr/local/bin/
 ```
 </details>
 <details><summary>Fedora Install Steps</summary>