apkbuild-lint: make removal of last match in grep for AL32 more robust

apkbuild-lint

@@ -265,7 +265,7 @@ braced_variable() {
 	# match end-of-line or a character that can't be in the name of a variable
 	grep -Eo -Hn -e '\$\{[A-Za-z0-9_]+\}($|["\./\(\)= -])' "$apkbuild" |
 		sed "s/^\([^:]*:[^:]*:\)\(.*\)/MP:[AL32]:\1unnecesary usage of braces: \2/" |
-		sed 's|.$||g' # This strips the last match in the grep
+		sed 's|[^}]$||g' # This strips the last match in the grep
 }
 
 cpan_variable() {