add autosign grains for minion

salt/files/minion.d/autosign_grains.conf

@@ -0,0 +1,11 @@
+#
+# This file is managed by Salt! Do not edit by hand!
+#
+{%- set autosign_grains = salt['pillar.get']('salt:autosign_grains', []) + salt['pillar.get']('salt:autosign_grains', []) + salt['pillar.get']('salt:minion:autosign_grains', []) -%}
+
+{%- if autosign_grains %}
+autosign_grains:
+  {%- for autosign_grain in autosign_grains %}
+  - '{{ autosign_grain }}'
+  {%- endfor -%}
+{%- endif -%}