diff --git a/.github/scripts/increment_build_number.sh b/.github/scripts/increment_build_number.sh
index cd2f60c..520455f 100644
--- a/.github/scripts/increment_build_number.sh
+++ b/.github/scripts/increment_build_number.sh
@@ -1,6 +1,7 @@
 export newVersion="$1"
 
 if [[ -n "$newVersion" ]]; then
+    #https://stackoverflow.com/a/30214769/13167574
     perl -i -pe 's/^(version:\s+)(\d+\.\d+\.\d+)(\+)(\d+)$/$1.$ENV{'newVersion'}.$3.($4+1)/e' pubspec.yaml
 else
     echo "argument error"