Change 'Evergreen' to 'evergreen' (lowercase)

Author: Darius Neațu

.github/workflows/sync-docs.yml

@@ -141,7 +141,7 @@ jobs:
           body: |
             Automated sync of documentation and images from latest content of [bemanproject/beman](https://github.com/bemanproject/beman).
             
-            Related to: #125 - Evergreen issue: automatic docs import
+            Related to: #125 - evergreen issue: automatic docs import
           labels: |
             sync
             automation