feat: actions: verify that container.options --hostname is valid

Refs: https://code.forgejo.org/forgejo/act/pulls/95

actions/example-config-options/.forgejo/workflows/test.yml

@@ -3,6 +3,8 @@ on: [push]
 jobs:
   test:
     runs-on: docker
+    container:
+        options: "--hostname customname"
     steps:
     - run: |
             test -f /srv/example-config-options-volume-valid
@@ -10,3 +12,5 @@ jobs:
             ! test -f /srv/example-config-options-volume-invalid
     - run: |
             test "$FROB" = "NITZ"
+    - run: |
+            test "$(cat /etc/hostname)" = customname

actions/example-config-options/runner-config.yaml

@@ -1,6 +1,7 @@
 
 log:
   level: debug
+  job_level: debug
 
 runner:
   file: .runner