fix(pacmak): fails when package path contains space (#2758)

Quoting the package path in the sub-shell command so that spaces are not
incorrectly interpreted as argument delimiters.

Fixes #2748

packages/jsii-pacmak/lib/packaging.ts

@@ -55,7 +55,9 @@ export class JsiiModule {
   public async npmPack() {
     this._tarball = await Scratch.make(async (tmpdir) => {
       logging.debug(`Running "npm pack ${this.moduleDirectory}" in ${tmpdir}`);
-      const args = ['pack', this.moduleDirectory];
+      // Quoting (JSON-stringifying) the module directory in order to avoid
+      // problems if there are spaces or other special characters in the path.
+      const args = ['pack', JSON.stringify(this.moduleDirectory)];
       if (logging.level >= logging.LEVEL_VERBOSE) {
         args.push('--loglevel=verbose');
       }