GEODE-3196: Fixing the format of the .md5 and .sha256 files

(cherry picked from commit 2ee271b134e6c49e0b7920bb147c475c03722c03)
diff --git a/gradle/release.gradle b/gradle/release.gradle
index 7f59c81..f429af2 100644
--- a/gradle/release.gradle
+++ b/gradle/release.gradle
@@ -30,8 +30,8 @@
     it.name.toLowerCase().contains("dist")
   }.each { archive ->
     archive.doLast {
-      ant.checksum file:"${archive.archivePath}", algorithm:"md5"
-      ant.checksum file:"${archive.archivePath}", algorithm:"sha-256", fileext:".sha256"
+      ant.checksum file:"${archive.archivePath}", algorithm:"md5", format: 'MD5SUM'
+      ant.checksum file:"${archive.archivePath}", algorithm:"sha-256", format: 'MD5SUM', fileext:".sha256"
       signing {
         required { !version.endsWith("SNAPSHOT") }
         sign archive.archivePath