use correct name for dnscrypt-proxy, subst underscore for hyphen in template var

bubble-server/src/main/resources/packer/roles/bubble/templates/bubble_versions.properties.j2

@@ -1,3 +1,3 @@
 algo_version={{ algo_version }}
-dnscrypt_version={{ dnscrypt_proxy_version }}
+dnscrypt_proxy_version={{ dnscrypt_proxy_version }}
 mitmproxy_version={{ mitmproxy_version }}