resmgr: strange datetime interpretation of name
If I add an entry…
```yaml
ocrd-eynollah-segment:
  - url: https://qurator-data.de/eynollah/2022-04-05/models_eynollah_renamed.tar.gz
    name: 2022-04-05
    description: models for eynollah
    type: tarball
    path_in_archive: 'models_eynollah'
    size: 1889719626
```
…then this is what I get…
```
06:59:37.278 ERROR ocrd.resource_manager - [ocrd-eynollah-segment.0.name] datetime.date(2022, 4, 5) is not of type 'string'
```

I have to prefix the name with some other string to get it working.
diff --git a/ocrd/ocrd/resource_manager.py b/ocrd/ocrd/resource_manager.py
index 4720cb54..0b66f523 100644
--- a/ocrd/ocrd/resource_manager.py
+++ b/ocrd/ocrd/resource_manager.py
@@ -9,6 +9,12 @@ from urllib.parse import urlparse, unquote
 import requests
 from yaml import safe_load, safe_dump
 
+# https://github.com/OCR-D/core/issues/867
+# https://stackoverflow.com/questions/50900727/skip-converting-entities-while-loading-a-yaml-string-using-pyyaml
+import yaml.constructor
+yaml.constructor.SafeConstructor.yaml_constructors[u'tag:yaml.org,2002:timestamp'] = \\
+    yaml.constructor.SafeConstructor.yaml_constructors[u'tag:yaml.org,2002:str']
+
 from ocrd_validators import OcrdResourceListValidator
 from ocrd_utils import getLogger
 from ocrd_utils.os import get_processor_resource_types, list_all_resources, pushd_popd
diff --git a/tests/test_resource_manager.py b/tests/test_resource_manager.py
index 21cd4520..ea30c6d2 100644
--- a/tests/test_resource_manager.py
+++ b/tests/test_resource_manager.py
@@ -104,5 +104,21 @@ def test_default_resource_dir(tmp_path):
     assert mgr.xdg_config_home != mgr.xdg_data_home
     assert mgr.default_resource_dir == str(mgr.xdg_data_home / 'ocrd-resources')
 
+def test_date_as_string(tmp_path):
+    mgr = OcrdResourceManager(xdg_data_home=tmp_path)
+    test_list = tmp_path / 'test-list.yml'
+    with open(test_list, 'w', encoding='utf-8') as fout:
+        fout.write("""\\
+    ocrd-eynollah-segment:
+      - url: https://qurator-data.de/eynollah/2022-04-05/models_eynollah_renamed.tar.gz
+        name: 2022-04-05
+        description: models for eynollah
+        type: tarball
+        path_in_archive: 'models_eynollah'
+        size: 1889719626
+        """)
+    mgr.load_resource_list(test_list)
+    mgr.list_available(executable='ocrd-eynollah-segment')
+
 if __name__ == "__main__":
     main(__file__)
['ocrd/ocrd/resource_manager.py', 'tests/test_resource_manager.py']