diff --git a/tools/release.js b/tools/release.js
index 4249995..f452e10 100644
--- a/tools/release.js
+++ b/tools/release.js
@@ -1,7 +1,7 @@
 const exec = require('child_process').execSync;
 const resolve = require('path').resolve;
 
-const getSHA = (s) => s.match(/^\s*([0-9a-fA-F]{40})\s*$/)[1];
+const getSHA = (s) => s.match(/^\s*([0-9a-f]{40})\s*$/i)[1];
 
 const inherit = { stdio: 'inherit' };
 const utf8 = { encoding: 'utf8' };