release: fix syntax error in verify_rc.sh (#782)

The previous commit didn't fix the issue because \ needs to be the final
character, or at least it does on my system.

Ref: #781 (comment)

Author: amoeba

dev/release/verify_rc.sh

@@ -66,7 +66,7 @@ setup_tmpdir() {
 download() {
   curl \
     --fail \
-    --location \    
+    --location \
     --show-error \
     --silent \
     --output "$2" \