chore: Streamline versions of camelcase & decamelize (#374)

Use the same versions that `yargs` uses in order to avoid having to
hoist multiple distinct versions in the overall dependency closure. This
also can cause issues in contexts where Node's multiple-version handling
is not available.

packages/codemaker/lib/case-utils.ts

@@ -1,15 +1,14 @@
-import * as camelcase from 'camelcase'
-import * as decamelize from 'decamelize'
+import { default as camelcase } from 'camelcase';
+import * as decamelize from 'decamelize';
 
 export function toCamelCase(...args: string[]) {
-    return camelcase(...args);
+    return camelcase(args);
 }
 
 export function toPascalCase(...args: string[]) {
-    const v = toCamelCase(...args);
-    return v.charAt(0).toUpperCase() + v.slice(1);
+    return camelcase(args, { pascalCase: true });
 }
 
 export function toSnakeCase(s: string, sep = '_') {
-    return decamelize(s, sep)
+    return decamelize(s, sep);
 }