fix: umd build expects cjs format

Signed-off-by: Gordon Smith <GordonJSmith@gmail.com>

Author: GordonSmith

packages/esbuild-plugins/src/build.ts

@@ -102,7 +102,7 @@ export function browserTpl(input: string, output: string, options: TplOptions =
     options.format = options.format ?? "esm";
 
     return buildWatch([input], {
-        format: options.format === "umd" ? "esm" : options.format,
+        format: options.format === "umd" ? "cjs" : options.format,
         external: options.external ?? [],
         outfile: `${output}.${options.format === "esm" ? "js" : `${options.format}.js`}`,
         platform: "browser",
@@ -125,7 +125,7 @@ export function nodeTpl(input: string, output: string, options: TplOptions = {})
     }
 
     return buildWatch([input], {
-        format: options.format === "umd" ? "esm" : options.format,
+        format: options.format === "umd" ? "cjs" : options.format,
         external: options.external ?? [],
         outfile: `${output}.${options.format === "esm" ? NODE_MJS : NODE_CJS}`,
         platform: "node",
@@ -145,7 +145,7 @@ export function neutralTpl(input: string, output: string, options: TplOptions =
     options.format = options.format ?? "esm";
 
     return buildWatch([input], {
-        format: options.format === "umd" ? "esm" : options.format,
+        format: options.format === "umd" ? "cjs" : options.format,
         external: options.external ?? [],
         outfile: `${output}.${options.format === "esm" ? "js" : `${options.format}.js`}`,
         platform: "neutral",