feat: Warn when trying to add directories that are absolute paths

An absolute path is tested for because we still want global installs to
work when the user is in the 'cellar/packages' folder

Author: hyperupcall

pkg/lib/commands/do-add.sh

@@ -20,6 +20,11 @@ do-add() {
 	fi
 
 	for repoSpec in "${pkgs[@]}"; do
+		if [[ -d "$repoSpec" && "${repoSpec::1}" == / ]]; then
+			log.warn "Identifier '$repoSpec' is a directory, not a package. Skipping"
+			continue
+		fi
+
 		util.extract_data_from_input "$repoSpec" "$with_ssh"
 		local uri="$REPLY1"
 		local site="$REPLY2"