[DEVOPS-836] test out putting the binary cache on S3

modules/hydra-master.nix

@@ -77,8 +77,13 @@ in {
     # auth token needs `repo:status`
     extraConfig = ''
       max_output_size = 4294967296
-      store-uri = file:///nix/store?secret-key=/etc/nix/hydra.iohk.io-1/secret
-      binary_cache_secret_key_file = /etc/nix/hydra.iohk.io-1/secret
+
+      store_uri = s3://iohk-nix-cache?secret-key=/etc/nix/hydra.iohk.io-1/secret&log-compression=br&region=eu-central-1
+      server_store_uri = https://iohk-nix-cache.s3-eu-central-1.amazonaws.com/
+      binary_cache_public_uri = https://iohk-nix-cache.s3-eu-central-1.amazonaws.com/
+      log_prefix = https://iohk-nix-cache.s3-eu-central-1.amazonaws.com/
+      upload_logs_to_binary_cache = true
+
       <github_authorization>
         input-output-hk = ${builtins.readFile ../static/github_token}
       </github_authorization>