Add config option for algo to use in temp_url tests

This is so to configure which hashlib algorithm should be used for
the temp_url tests, defaulting to sha256 but preserving the
ability to use sha1 for compatibility with other Swift implementations.

Change-Id: Ia4923d47870fcb914a33adecb7155763ec1d0b2f
diff --git a/releasenotes/notes/temp_url_tests_digest_config-3d8c9bb271961ddd.yaml b/releasenotes/notes/temp_url_tests_digest_config-3d8c9bb271961ddd.yaml
new file mode 100644
index 0000000..f96c030
--- /dev/null
+++ b/releasenotes/notes/temp_url_tests_digest_config-3d8c9bb271961ddd.yaml
@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Add configuration parameter `tempurl_digest_hashlib` into
+    `object-storage-feature-enabled` which configures the hashing algorithm to
+    use for the temp_url tests; defaults to 'sha256'.
+security:
+  - |
+    Swift used to support only 'sha1' for temp_url hashing but from many
+    years now 'sha256' and 'sha512' are also available. These are stronger
+    than 'sha1' and tempest now allows configuring which one to use.