fix readme check

This is needed to work around a strange behaviour in git diff-index, where a
file that has a different modification time but the same content shows up as
modified until git update-index --refresh is run.

Author: christophgysin

check-if-readme-is-up-to-date.sh

@@ -2,10 +2,14 @@
 
 echo "Checking if README.md has been updated..."
 
-if ! git diff-index --quiet HEAD README.md; then
+git update-index --refresh
+
+if ! git diff-index --quiet HEAD -- README.md; then
     echo "README.md needs to be regenerated!"
     echo
     echo "Please run:"
     echo "  $ npm run docs"
     exit 1
 fi
+
+exit 0