Fixes unescaped left brace in regex to pass test 010dependencies.t

Fix by David Denoncin, based on the 5.0.3 patch

https://bugzilla.mozilla.org/show_bug.cgi?id=228444

--- a/t/010dependencies.t	2020-06-09 21:21:28.049161109 -0000
+++ b/t/010dependencies.t	2020-06-09 21:21:07.059161235 -0000
@@ -71,7 +71,7 @@
         $used =~ s#/#::#g;
         $used =~ s#\.pm$##;
         $used =~ s#\$module#[^:]+#;
-        $used =~ s#\${[^}]+}#[^:]+#;
+        $used =~ s#\$\{[^}]+}#[^:]+#;
         $used =~ s#[" ]##g;
         push(@use, grep(/^\Q$used\E$/, keys %mods));
       }