Merge pull request #51544 from rhiroe/doc/Updated-the-default-digest-…

…algorithm-used-for-key-derivation-in-ActiveRocord-Encryption-to-SHA256

Update the guide reference on the default digest algorithm used
for key derivation in ActiveRecord Encryption to SHA256. [ci skip]

guides/source/active_record_encryption.md

@@ -490,7 +490,7 @@ The default encoding for attributes encrypted deterministically. You can disable
 
 #### `config.active_record.encryption.hash_digest_class`
 
-The digest algorithm used to derive keys. `OpenSSL::Digest::SHA1` by default.
+The digest algorithm used to derive keys. `OpenSSL::Digest::SHA256` by default.
 
 #### `config.active_record.encryption.support_sha1_for_non_deterministic_encryption`