fix newline issues when passing args directly to binary instead of bash

src/lib.js

@@ -20,10 +20,14 @@ export async function installFpmViaRuby(debug) {
 export async function executeFpmBuild(computedFpmArgs, debug) {
 
   const userFpmArgs = core.getInput('fpm_args');
-  const fpmCmd      = 'fpm'
+  let fpmCmd        = 'fpm'
     + ' ' + computedFpmArgs
     + ' ' + userFpmArgs;
 
+  fpmCmd = fpmCmd.replaceAll('\n', ' ')
+                 .replaceAll('\\n', ' ')
+                 .replaceAll('\\', ' ');
+
   if (debug) {
     console.log('fpm command: ', fpmCmd);
   }