Don't generate empty deps = [] in generated build files

internal/npm_install/generate_build_file.js

@@ -707,6 +707,16 @@ function printPackage(pkg) {
     ],`;
   }
 
+  let depsStarlark = '';
+  if (pkgDeps.length) {
+    depsStarlark = `
+    # flattened list of direct and transitive dependencies hoisted to root by the package manager
+    deps = [
+        ${
+        pkgDeps.map(dep => `"//node_modules/${dep._dir}:${dep._name}__files",`).join('\n        ')}
+    ],`;
+  }
+
   let result = `load("@build_bazel_rules_nodejs//:defs.bzl", "nodejs_binary")
 load("@build_bazel_rules_nodejs//internal/npm_install:node_module_library.bzl", "node_module_library")
 
@@ -718,12 +728,7 @@ node_module_library(
     # ${pkg._dir} package contents (and contents of nested node_modules)
     srcs = [
         ":${pkg._name}__files",
-    ],
-    # flattened list of direct and transitive dependencies hoisted to root by the package manager
-    deps = [
-        ${
-      pkgDeps.map(dep => `"//node_modules/${dep._dir}:${dep._name}__files",`).join('\n        ')}
-    ],
+    ],${depsStarlark}
 )
 
 # ${pkg._name}__files target is used as dep for other package targets to prevent