Add the new config key to the YAML config-show gold file

Same reason as the JSON one: ConfigShowYAMLTest snapshots `aptly config
show` in YAML form. Checked all three gold files under t02_config this
time rather than the one CI named. CreateConfigTest_gold is a commented
template rather than struct output, so it is unaffected, and it passes.

system/t02_config/ConfigShowYAMLTest_gold

@@ -3,6 +3,11 @@ log_level: debug
 log_format: default
 database_open_attempts: 10
 architectures: []
+acquire_by_hash_algorithms:
+    - MD5Sum
+    - SHA1
+    - SHA256
+    - SHA512
 skip_legacy_pool: false
 dep_follow_suggests: false
 dep_follow_recommends: false