nixos/acme: rename option credentialsFile to environmentFile

nixos/modules/security/acme/default.md

···
 security.acme.certs."example.com" = {
   domain = "*.example.com";
   dnsProvider = "rfc2136";
-  credentialsFile = "/var/lib/secrets/certs.secret";
+  environmentFile = "/var/lib/secrets/certs.secret";
   # We don't need to wait for propagation since this is a local DNS server
   dnsPropagationCheck = false;
 };
···
 security.acme.defaults.email = "[e-mail]";
 security.acme.defaults = {
   dnsProvider = "rfc2136";
-  credentialsFile = "/var/lib/secrets/certs.secret";
+  environmentFile = "/var/lib/secrets/certs.secret";
   # We don't need to wait for propagation since this is a local DNS server
   dnsPropagationCheck = false;
 };

nixos/modules/security/acme/default.nix

···
           "/var/lib/acme/.lego/${cert}/${certDir}:/tmp/certificates"
         ];
 
-        # Only try loading the credentialsFile if the dns challenge is enabled
-        EnvironmentFile = mkIf useDns data.credentialsFile;
+        # Only try loading the environmentFile if the dns challenge is enabled
+        EnvironmentFile = mkIf useDns data.environmentFile;
 
         Environment = mkIf useDns
           (mapAttrsToList (k: v: ''"${k}=%d/${k}"'') data.credentialFiles);
···
       defaultText = if isDefaults then default else literalExpression "config.security.acme.defaults.${name}";
     };
   in {
+    imports = [
+      (mkRenamedOptionModule [ "credentialsFile" ] [ "environmentFile" ])
+    ];
+
     options = {
       validMinDays = mkOption {
         type = types.int;
···
         '';
       };
 
-      credentialsFile = mkOption {
+      environmentFile = mkOption {
         type = types.nullOr types.path;
-        inherit (defaultAndText "credentialsFile" null) default defaultText;
+        inherit (defaultAndText "environmentFile" null) default defaultText;
         description = lib.mdDoc ''
           Path to an EnvironmentFile for the cert's service containing any required and
           optional environment variables for your selected dnsProvider.

nixos/tests/acme.nix

···
   dnsConfig = nodes: {
     dnsProvider = "exec";
     dnsPropagationCheck = false;
-    credentialsFile = pkgs.writeText "wildcard.env" ''
+    environmentFile = pkgs.writeText "wildcard.env" ''
       EXEC_PATH=${dnsScript nodes}
       EXEC_POLLING_INTERVAL=1
       EXEC_PROPAGATION_TIMEOUT=1