Updated the install_shellcheck.sh script to run a cleaner installatio…

…n by removing the shellcheck folder after the shellcheck executable is added to the path

src/install_shellcheck.sh

@@ -1,8 +1,8 @@
 #!/bin/bash
 
-# Update shellcheck to the locked v0.7.0 version through the binary distribution
 scversion='v0.7.2'
 
 wget -qO- "https://github.com/koalaman/shellcheck/releases/download/${scversion?}/shellcheck-${scversion?}.linux.x86_64.tar.xz" | tar -xJv
 cp "shellcheck-${scversion}/shellcheck" /usr/local/bin
+rm -rf "shellcheck-${scversion}"
 shellcheck --version