Make the Github token optional (#1390)

A default is useless when the variable
is required.

.github/workflows/auto-release.yml

diff --git a/.github/workflows/auto-release.yml b/.github/workflows/auto-release.yml
index 21ab088..c1786ac 100644
--- a/.github/workflows/auto-release.yml
+++ b/.github/workflows/auto-release.yml
@@ -17,7 +17,7 @@
         default: ''
       github_token:
         description: 'GitHub token for creating releases and pushing changes'
-        required: true
+        required: false
         default: ${{ github.token }}
 
 jobs: