r/gitea: Update to 1.17.0

The only major change that affects the configuration policy is the
introduction of the `webhook.ALLOWED_HOST_LIST` setting.  For some dumb
reason, the default value of this setting *denies* access to machines on
the local network.  This makes no sense; why do they expect you to host
your CI or whatever on a *public* network?  Of course, the only reason
given is "for security reasons."

roles/gitea/tasks/main.yml

@@ -31,7 +31,7 @@
   get_url:
     url: '{{ gitea_download_url }}'
     dest: 'roles/gitea/files/{{ gitea_bin }}'
-    checksum: 'sha256:{{ gitea_bin_sha256 }}'
+    checksum: '{{ gitea_bin_sha256 }}'
   tags:
   - download
 - name: ensure gitea is installed