Exclude files/issue and files/motd from end-of-file-fixer

These files may intentionally have one or more blank lines at the end,
so we do not want the end-of-file-fixer pre-commit linter to change
them.

.pre-commit-config.yaml

@@ -28,6 +28,7 @@ repos:
           - --allow-missing-credentials
       - id: detect-private-key
       - id: end-of-file-fixer
+        exclude: files/(issue|motd)
       - id: mixed-line-ending
         args:
           - --fix=lf