Fix security issue with actor validation

[corest]

No description provided.

[oppiliappan]

Suggested change

	for member in $(echo ${members}); do
	if [[ $member = $ACTOR ]]; then
	echo "is-member=true" >> $GITHUB_OUTPUT
	fi
	done
	for member in "${members[@]}"; do
	[[ "$member" == "$ACTOR" ]] && echo "is-member=true" >> $GITHUB_OUTPUT
	done

or we could change grep to use -F and -w.

[corest]

I like to be explicit. Also this piece doesn't work in my shell