Fix shellcheck

Author: ocelotl

tox.ini

@@ -442,7 +442,7 @@ commands =
 [testenv:shellcheck]
 
 commands_pre =
-  sudo apt update && sudo apt install --assume-yes shellcheck
+  sh -c "sudo apt update -y && sudo apt install --assume-yes shellcheck"
 
 commands =
-  find . -name \*.sh | xargs shellcheck --severity=warning
+  sh -c "find {toxinidir} -name \*.sh | xargs shellcheck --severity=warning"