ignore --ignore-cr-at-eol for old gits

.scripts/release-pre.sh

@@ -32,8 +32,10 @@ if ! [[ -d ulib ]]; then
 fi
 
 # Fail if the state is dirty
-git diff --staged --exit-code --ignore-cr-at-eol
-git diff --exit-code --ignore-cr-at-eol
+# NOTE: --ignore-cr-at-eol is a recent option,
+# so we should ignore it if it is not there
+git diff --staged --exit-code --ignore-cr-at-eol || git diff --staged --exit-code
+git diff --exit-code --ignore-cr-at-eol || git diff --exit-code
 
 # Detect the F* version number
 git fetch --tags $git_remote