Add note on using synapse s3 provider git version for sse-c support

docs/configuring-playbook-synapse-s3-storage-provider.md

@@ -45,6 +45,8 @@ matrix_synapse_ext_synapse_s3_storage_provider_config_storage_class: STANDARD #
 matrix_synapse_ext_synapse_s3_storage_provider_config_sse_customer_enabled: true
 matrix_synapse_ext_synapse_s3_storage_provider_config_sse_customer_key: ssec-key-goes-here # Generate with: cat /dev/urandom | head -c 32 | base64 -
 matrix_synapse_ext_synapse_s3_storage_provider_config_sse_customer_algo: AES256
+# Using the git version is also required until > v1.1.2 is released
+matrix_synapse_ext_synapse_s3_storage_provider_version: git
 
 # For additional advanced settings, take a look at `roles/custom/matrix-synapse/defaults/main.yml`
 ```