treefmt: enable prettier

.gitignore

@@ -6,3 +6,6 @@ result-*
 .terraform
 .terraform.*
 /terraform/.direnv
+
+# needed for treefmt
+!.github

treefmt.nix

@@ -9,6 +9,8 @@
 
       programs.hclfmt.enable = true;
 
+      programs.prettier.enable = true;
+
       settings.formatter = {
         nix = {
           command = "sh";
@@ -31,6 +33,13 @@
           ];
         };
 
+        prettier = {
+          excludes = [
+            "*.md"
+            "secrets.yaml"
+          ];
+        };
+
         python = {
           command = "sh";
           options = [