patch 8.2.2237: CI on Mac fails in sed command

Problem:    CI on Mac fails in sed command.
Solution:   Set LC_ALL to "C". (Ozaki Kiichi, closes #7565)
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 40a2ce3..adbbb1f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -291,7 +291,7 @@
 
       - name: Build
         env:
-          LANG: C
+          LC_ALL: C
         run: |
           make -j${NPROC}