Upgrade mjolnir-antispam (1.4.0 -> v1.6.4)

roles/custom/matrix-synapse/defaults/main.yml

@@ -825,7 +825,7 @@ matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeserve
 # See: https://github.com/matrix-org/mjolnir#synapse-module
 matrix_synapse_ext_spam_checker_mjolnir_antispam_enabled: false
 matrix_synapse_ext_spam_checker_mjolnir_antispam_git_repository_url: "https://github.com/matrix-org/mjolnir"
-matrix_synapse_ext_spam_checker_mjolnir_antispam_git_version: "4008e3f65d3745b9307dd31f1c5aa80c13a61a58"
+matrix_synapse_ext_spam_checker_mjolnir_antispam_git_version: "v1.6.4"
 matrix_synapse_ext_spam_checker_mjolnir_antispam_config_block_invites: true
 # Flag messages sent by servers/users in the ban lists as spam. Currently
 # this means that spammy messages will appear as empty to users. Default